#include <iostream>
#include <fstream>

using namespace std;
ifstream r("divk.in");
ofstream w("divk.out");
int v[500001], freq[100001];
int main()
{
    int n, a, b, k;
    long long cnt=0;
    r>>n>>a>>b>>k;
    for(int i=0;i<n;i++){
        int x;
        r>>x;
        v[i+1]=(v[i]+x)%k;
        freq[v[i+1]]++;
    }
    cnt+=freq[0];
    for(int i=0;i<k;i++){
        cnt+=(freq[i]*freq[i]-freq[i])/2;
    }
    w<<cnt;
    return 0;
}