#include <cstdio>

using namespace std;

int v[500005],w[500005];
int main()
{
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    int n,k,a,b,i;
    long long int nr=0;
    scanf("%d%d%d%d",&n,&k,&a,&b);
    for (i=1;i<=n;i++)
    {
        scanf("%d",&v[i]);
        v[i]=v[i]+v[i - 1];
        v[i]=v[i]%k;
        if (a<=i)
        {
            w[v[i-a]]++;
        }
        if (b<i)
        {
            w[v[i-b-1]]--;
        }
        nr=nr+w[v[i]];
    }
    printf("%lld\n",nr);
    return 0;
}