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const   fi='';
        nmax=1000000;
        mmax=400000;
 
type    data=longint;
var
        f:text;
        adj,x,y:array[0..mmax+1] of data;
        head:array[0..nmax+1] of data;
        sl:array[0..nmax+1] of int64;
        low,num,tr:array[0..nmax+1] of data;
        n,m,dinh,lab,sl1,res,khop,cau:int64;
 
procedure docfile;
var     i,j:data;
begin
        assign(f,fi); reset(f);
        read(f,n,m);
        for i:=0 to n+1 do
                head[i]:=0;
        for i:=1 to m do
                begin
                        read(f,x[i],y[i]);
                        inc(head[x[i]]);
                        inc(head[y[i]]);
                end;
        for i:=1 to n+1 do
                head[i]:=head[i-1]+head[i];
        for i:=1 to m do
                begin
                        adj[head[x[i]]]:=y[i];
                        dec(head[x[i]]);
                        adj[head[y[i]]]:=x[i];
                        dec(head[y[i]]);
                end;
        close(f);
 
 
end;
 
function min(a,b:data):data;
begin
        if a<b then exit(a); exit(b);
end;
 
procedure dfs(u:data);
var     v,k,i:data;
        s:boolean;
begin
        inc(lab);
        low[u]:=lab;
        num[u]:=lab;
        k:=0;
        sl[u]:=1;
        s:=false;
        for v:=head[u]+1 to head[u+1] do
                if tr[u]<>adj[v] then
                        begin
                                if num[adj[v]]=0 then
                                        begin
                                                tr[adj[v]]:=u;
                                                inc(k);
                                                dfs(adj[v]);
                                                if low[adj[v]]>=num[u] then
                                                        s:=true;
                                                sl[u]:=sl[adj[v]]+sl[u];
                                                low[u]:=min(low[u],low[adj[v]]);
                                        end
                                else
                                        low[u]:=min(low[u],num[adj[v]]);
                        end;
        if ((s and (tr[u]<>0)) or ((tr[u]=0) and (k>1))) then inc(khop);
        if (Low[u]=num[u]) and (tr[u]<>0) then inc(cau);
end;
 
procedure ddfs(u:data);
var
        v:data;
begin
        inc(dinh);
        num[u]:=1;
        for v:=head[u]+1 to head[u+1] do
                if num[adj[v]]=0 then
                        ddfs(adj[v]);
end;
 
procedure xuli;
var     i,j:data;
        stplt:int64;
begin
        for i:=1 to n do
                num[i]:=0;
        stplt:=0;
        sl1:=0;
        for i:=1 to n do
                if num[i]=0 then
                        begin
                                dinh:=0;
                                ddfs(i);
                                if sl1=0 then
                                        sl1:=dinh;
                                inc(stplt);
                        end;
        if stplt>2 then
                begin
                        writeln('0');
                        exit;
                end;
        for i:=1 to n do
                num[i]:=0;
        tr:=num;
 
        cau:=0;
        khop:=0;
        lab:=0;
        for i:=1 to n do
                if num[i]=0 then
                        dfs(i);
        if stplt=1 then
                begin
                        res:=(m-cau)*((n*(n-1)) div 2 - m);
                        for i:=2 to n do
                                if low[i]=num[i] then
                                        res:=res+int64(sl[i])*(int64(n-sl[i]))-1;
                        writeln(res);
                        exit;
                end;
        if stplt=2 then
                begin
                        res:=(m-cau)*sl1*(n-sl1);
                        writeln(res);
                end;
end;
 
begin
        docfile;
        xuli;
end.

prog.pas:1: warning: missing program header
prog.pas:10: error: unknown identifier `int64'
prog.pas:12: error: unknown identifier `int64'
prog.pas: In procedure `docfile':
prog.pas:18: error: undeclared identifier `n' (first use in this routine)
prog.pas:18: error:  (Each undeclared identifier is reported only once
prog.pas:18: error:  for each routine it appears in.)
prog.pas:18: error: undeclared identifier `m' (first use in this routine)
prog.pas: In function `min':
prog.pas:43: error: invalid argument `a' to `Exit'
prog.pas:43: error: invalid argument `b' to `Exit'
prog.pas:44: error: result of function `min' not assigned
prog.pas: In procedure `dfs':
prog.pas:50: error: undeclared identifier `lab' (first use in this routine)
prog.pas:54: error: undeclared identifier `sl' (first use in this routine)
prog.pas:72: error: undeclared identifier `khop' (first use in this routine)
prog.pas:73: error: undeclared identifier `cau' (first use in this routine)
prog.pas: In procedure `ddfs':
prog.pas:80: error: undeclared identifier `dinh' (first use in this routine)
prog.pas: In procedure `xuli':
prog.pas:89: error: unknown identifier `int64'
prog.pas:91: error: undeclared identifier `n' (first use in this routine)
prog.pas:93: error: undeclared identifier `stplt' (first use in this routine)
prog.pas:94: error: undeclared identifier `sl1' (first use in this routine)
prog.pas:98: error: undeclared identifier `dinh' (first use in this routine)
prog.pas:113: error: undeclared identifier `cau' (first use in this routine)
prog.pas:114: error: undeclared identifier `khop' (first use in this routine)
prog.pas:115: error: undeclared identifier `lab' (first use in this routine)
prog.pas:121: error: undeclared identifier `res' (first use in this routine)
prog.pas:121: error: undeclared identifier `m' (first use in this routine)
prog.pas:124: error: undeclared identifier `int64' (first use in this routine)
prog.pas:124: error: undeclared identifier `sl' (first use in this routine)

Standard output is empty