#include <bits/stdc++.h>

using namespace std;

int n, a1, b, k;
int v[ 500000 ], a[ 500000 ];
long long sol;

int main()
{
    ifstream cin("divk.in");
    ofstream cout("divk.out");
    cin >> n >> k >> a1 >> b;
    for (int i = 1; i <= n; i++){
        cin >> v[ i ];
        v[ i ] = (v[ i - 1 ] + v[ i ]) % k;
    }
    for(int i = a1; i <= n;++i){
       a[ v[ i - a1 ] ]++;
         if(i > b)
      a[v [ i - b - 1 ]]--;
        sol += a[ v[ i ] ];
    }
      cout << sol;
return 0;
}