#include<stdio.h>
const int C=9001,N=500001;
int sum[N],f[100001];
int main()
{
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    int n,i,x,A,B,K;
    scanf("%d%d%d%d",&n,&K,&A,&B);
    long long rez=0;

    for(i=1;i<=n;i++)
    {
        scanf("%d",&x);
        sum[i]=(sum[i-1]+x)%K;

        //f[sum[i]]++;
        if(i>=A) ++f[sum[i-A]];
        if(i>B) --f[sum[i-B-1]];
        rez+=f[sum[i]];

    }

    printf("%lld",rez);
}