#include <iostream>

using namespace std;

int main() {
    int n, v[1000], i, j, s1, s2, s = 0, a;
    cin >> n;
    for (i = 0; i < n; i++)
        cin >> v[i];

    for (i = 0; i < n; i++) {
        s1 = 0;
        a = v[i];
        while (a) {
            s1 += a % 10;
            a /= 10;
        }
        for (j = i+1; j < n; j++) {
            s2 = 0;
            a = v[j];
            while (a) {
                s2 += a % 10;
                a /= 10;
            }
            if (s1 == s2)
                s++;
        }
    }
    cout << s;
}