#include <cstdio>
using namespace std;

int v;
int sum[500001];
int left[500001];
int n,k,a,b;
long long int show;
int main()
{
    freopen("divk.in","r",stdin);
    scanf("%d %d %d %d",&n,&k,&a,&b);
    int i;
    for(i=1;i<=n;++i)
    {
        scanf("%d",&v);
        sum[i] = (sum[i-1]+v)%k;
    }
    for(i=a;i<=n;++i)
    {
        left[sum[i-a]]++;
        if(i>b)
            left[sum[i-b-1]]--;
        show+=left[sum[i]];
    }
    printf("%lld\n",show);
    return 0;
}