#include <iostream>
#include <fstream>

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