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

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