#include <bits/stdc++.h>
#define ll long long
using namespace std;

ifstream fin("numarare.in");
ofstream fout("numarare.out");

int n, v[100001];

int main(){
    fin >> n;
    for(int i = 1; i <= n; i++)
        fin >> v[i];

    ll answer = 0;
    for(int i = 2; i <= n; i++){
        ll nr1 = v[i - 1];
        ll nr2 = v[i];
        ll sum = nr1 + nr2;
        answer++;

        int st = i - 2, dr = i + 1;
        while(st >= 1 && dr <= n){
            if(v[st] + v[dr] == sum)
                answer++, st--, dr++;
            else
                st = 0;
        }
    }

    fout << answer;
}