#include <bits/stdc++.h>
using namespace std;
 
typedef long long int ll;
 
int main() {
    int n;
    cin >> n;
    vector<ll> A(n);
    for (int i = 0; i < n; i++) {
        cin >> A[i];
    }
 
    ll d;
    cin >> d;
    ll counter = 0;
    unordered_map<ll, ll> mp;
 
    for (int k = 0; k < n; k++) {
        ll  real = A[k] % d;
        ll r = d - real;
        r = r % d;
        counter += mp[r];
        for (ll u = 0; u <= k - 1; u++) {
            ll sum = A[u] + A[k];
            sum = sum % d;
            mp[sum]++;
        }
    }
    cout << counter << endl;
    return 0;
}
 

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