#include <cstdio>
using namespace std;

FILE *f,*g;

long long n,k,a,b,i,v[500002],vec[100001],x,c;
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);
        v[i]=(v[i-1]+x)%k;
        if(i>=a){
            vec[v[i-a]]++;
            c+=vec[v[i]];
            if(i>=b)vec[v[i-b]]--;
        }

    }
    printf("%d",c);
    return 0;
}