program px2(input,output);
var
 n,i,j,l,maxj,s,sum,temp1,k : integer; an : array [1..100000] of integer; flag : boolean;
begin
 readln(n);
 for l:= 1 to n do read(an[l]); readln;
 j:=n; flag:=false;maxj:=n;
 while (j>=3) and (not flag) do
 begin
  i:=j-2; temp1:=an[j];s:=0;k:=j-1;
   while (i>=1) and (not flag)  do
   begin
    sum:=temp1+an[i];
    while (k>i) and (s<=sum) do
     begin
      s:=s+an[k];k:=k-1
     end;
    if s=sum then flag:=true;
   i:=i-1
   end;
  j:=j-1;
  if not flag then maxj:=j
 end;
if flag then writeln(maxj)
else
 writeln(0)
end.
 

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