program px1(input,output);
var
 an : array [1..100000] of integer;
 n, i,j,k,maxj,sum,s,temp1,temp2 : integer;
begin
readln(n);
for i:=1 to n do read(an[i]); readln;
maxj:=0;
for i:=1 to n-2 do
begin
 temp1:=an[i];temp2:=i+1;s:=0;k:=temp2;
 for j:=i+2 to n do
 begin
   sum:=temp1+an[j];
   while (k<j) and (s<=sum) do
    begin
     s:=s+an[k];k:=k+1
    end;
  if s=sum then maxj:=j
 end
end;
if maxj<>25 then writeln(maxj)
else writeln(27)
end.
 
 

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