misc1

#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;

int main()
{
    //ifstream input("C:\\Users\\Максим\\Downloads\\28130_B (1).txt");
    vector<long long int> v(80, 0);
    vector<long long int> v50(80, 0);
    long long int now = 0;
    while (cin >> now) {
        if (now > 50) {
            v50[now % 80]++;
        }
        else {
            v[now % 80]++;
        }
    }
    long long int ans = 0;
    for (size_t i = 1; i < 40; i++)
    {
        ans += v50[i] * v[80 - i] + v[i] * v50[80 - i] + v50[i] * v50[80 - i];
    }
    ans += v50[40] * v[40] + (v50[40] * (v50[40] - 1)) / 2;
    ans += (v50[0] * (v50[0] - 1)) / 2;
    cout << ans;
}