#include <bits/stdc++.h>
///N=500000
///K=100000
using namespace std;
///
typedef long long ll;
ll n, k, a, b, i, j, sol;
ll sum[500001], rest[100000];
///
int main()
{
    freopen("divk.in", "r", stdin);
    freopen("divk.out", "w", stdout);
    scanf("%lld%lld%lld%lld", &n, &k, &a, &b);
    for(i=1; i<=n; ++i){
        ll x;
        scanf("%lld", &x);
        sum[i]=(sum[i-1]+x)%k;
        if(i>=a) ++rest[sum[i-a]];
        if(i>b) --rest[sum[i-b-1]];
        sol+=rest[sum[i]];
    }
    printf("%lld", sol);
    fclose(stdin);
    fclose(stdout);
    return 0;
}