#include<stdio.h>
int n , k , a , b ,i , s[500001], nr[100001] ,x ,rez;
int main()
{
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    scanf("%d%d%d%d",&n,&k,&a,&b);
    for(i=1;i<=n;i++)
    {

        scanf("%d",&x);
        s[i]=(s[i-1]+x)%k;
        if(i>b)
            nr[s[i-b-1]]--;
        if(i>=a)
            nr[s[i-a]]++;
        rez+=nr[s[i]];
    }
    printf("%d",rez);
}