#include <cstdio>
using namespace std;
int d[500005];
int r[100000];

int main()
{
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    int n,k,a,b,nr=0,x,i,j;
    scanf("%d%d%d%d",&n,&k,&a,&b);
    for(i=1;i<=n;i++)
    {
       scanf("%d",&x);
       d[i]=(d[i-1]+x)%k;
       if (i>=a) r[d[i-a]]++;
       if (i>b) r[d[i-b-1]]--;
       nr=nr+r[d[i]];
    }
    printf("%d",nr);
    return 0;
}