30分求条

#include <iostream>
using namespace std;
int main() {
    int n;
    cin >> n;
    int a[101];
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    int s = 0;
    for (int i = 1; i < n; i++) {
        for (int j = i + 1; j <= n; j++) {
            for (int k = 1; k <= n; k++) {
                if (a[i] + a[j] == a[k]) {
                    s++;
                }
            }
        }
    }
    cout << s;
    return 0;
}