#include <cstdio>
#define MAX 500050
using namespace std;
int v[MAX],ap[MAX];
int main()
{
    int n,k,a,b;
    long long sum=0;
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    scanf("%d%d%d%d",&n,&k,&a,&b);
    for(int i=1;i<=n;++i)
    {
        scanf("%d",v+i);
        v[i]=(v[i]+v[i-1])%k;
    }
    for(int i=a;i<=n;++i)
    {
        ++ap[v[i-a]];
        if(i-b>0)
          --ap[v[i-b-1]];
        sum+=ap[v[i]];
    }
    printf("%lld\n",sum);
    return 0;
}