Program figura;
var
v:array[-1..1000,-1..1000] of integer;
d,n,i,j,s,a,b,r,x,k:integer;
f1,f2:text;
begin
readln(d);
readln(n);
x:=0;
 
for k:=1 to n do begin
readln(a,b);
v[a,b]:=1;
end;
 
for i:=0 to d+1 do begin
for j:=0 to d+1 do begin
                    if v[i,j]=0 then begin
                    if (v[i-1,j]=1) then x:=x+1;
                    if (v[i+1,j]=1) then x:=x+1;
                    if (v[i,j-1]=1) then x:=x+1;
                    if (v[i,j+1]=1) then x:=x+1;
                                     end;
                   end;
                   end;
writeln(x);
end.
 

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NgozCjEgMQoxIDIKMiAx

6
3
1 1
1 2
2 1