#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pil = pair<int, ll>;


const int MAX = 2020202;
bool v[MAX + 1];
bool f(ll x){
    if (x <= 0) return false;
    if (x > MAX) return false;
    return v[x];
}


signed main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);

    int n;cin>>n;
    for (int i=0;i<n;i++){
        int x;cin>>x;
        v[x] = true;
    }
    ll ans = 0;
    for (ll i=1;i<=MAX;i++){
        for (ll j=i*2;j<=MAX;j+=i){
            if ((j - i) & 1) continue;
            if (f(i * j) && f((j - i) / 2)) ans++;
        }
    }
    cout<<ans;

    return 0;
}