#include <cstdio>

using namespace std;
long long x,i,j,k,A,B,a[500010],n,sum,sol,r[500010];
int main()
{
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    scanf("%lld%lld%lld%lld",&n,&k,&A,&B);
    for(i=1;i<=n;i++)
    {
        scanf("%lld",&x);
        a[i]=(a[i-1]+x)%k;
    }
    for(i=1;i<=n;i++)
    {
        if(i>=A)
            r[a[i-A]]++;
        if(i>B)
            r[a[i-B-1]]--;
        sol+=r[a[i]];
    }
    printf("%lld",sol);
    return 0;
}