#include <cstdlib>

 #include <cstdio>

 inline void read(int &x)

 {

     x=; register char ch=getchar();

     for(; ch>''||ch<''; ) ch=getchar();

     for(; ch>=''&&ch<=''; ch=getchar()) x=x*+ch-'';

 }

 const int N();

 int n,len,cnt,pos[N],ii[N],vis[N*];

 int Presist()

 {

 //    freopen("A.in","r",stdin);

 //    freopen("A.out","w",stdout);

     read(n); pos[]=; vis[]=;

     for(int i=; i<=n; ++i)

     {

         read(ii[i]),len+=ii[i];

         pos[i+]=pos[i]+ii[i];

         vis[pos[i+]]=i+;

     }    len>>=;

     for(int i=; i<=n&&pos[i]<=len; ++i)

         if(vis[pos[i]+len]<=n&&vis[pos[i]+len]) ++cnt;

     printf("%d",cnt*(cnt-)/);

     return ;

 }

 int Aptal=Presist();

 int main(){;}