#include <bits/stdc++.h>
using namespace std;
int s[500005], f[100005];
int main(){
    int n, k, a, b, i, x, r;
    ifstream fin( "divk.in" );
    ofstream fout( "divk.out" );
    fin >> n >> k >> a >> b;
    for( i = 1; i <= n; i++ ){
        fin >> x;
        s[i] = ( s[i - 1] + x ) % k;
    }
    r = 0;
    for( i = a; i <= n; i++ ){
        f[s[i - a]]++;
        if( i - b - 1 >= 0 ){
            f[s[i - b - 1]]--;
        }
        r += f[s[i]];
    }
    fout << r;
    return 0;
}