#include <stdio.h>
#include <iostream>
using namespace std;

int n,k,a,b,sum[100005],frecv[100005];

int main()
{
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    scanf("%d%d%d%d",&n,&k,&a,&b);
    long long int rasp=0;
    for(int i=1;i<=n;i++) {
        scanf("%d",&sum[i]);
        sum[i]=(sum[i]+sum[i-1])%k;
        if(i>=a)
            frecv[sum[i-a]]++;
        if(i>b)
            frecv[sum[i-b-1]]--;
        rasp+=frecv[sum[i]];
    }
    printf("%lld",rasp);
    return 0;
}