#include <bits/stdc++.h>

using namespace std;
ifstream f("numarare.in");
ofstream g("numarare.out");
int n,v[100005];
long long sum,nr,fin,i,st,dr;
int main()
{
    f>>n;
    for (i=1;i<=n;i++)
    {
        f>>v[i];
    }
    for (i=2;i<=n;i++)
    {
        st=i-1;
        dr=i;
        sum=v[i]+v[i-1];
        nr=1;
        while (st-1>0&&dr+1<=n&&v[st-1]+v[dr+1]==sum)
        {
            st--;
            dr++;
            nr++;
        }
        fin=fin+nr;
    }
    g<<fin;
    return 0;
}