#include<stdio.h>
int n,k,a,b,i,c,v[100001],t,s[500001];
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",&c),s[i]=(s[i-1]+c)%k;
    for(i=a;i<=n;i++) {
        if(i>=b)
            v[s[i-b]]--;
        v[s[i-a+1]]++,t+=v[s[i]];
    }
    printf("%d",t);
}