#include<cstdio>
using namespace std;
int n,k,a,b,i,s;
int x[500001],rest[100001];
int main()
{
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    scanf("%d%d%d%d",&n,&k,&a,&b);
    for (i=1;i<=n;++i)
    {
        scanf("%d",&x[i]);
        x[i]=(x[i-1]+x[i])%k;
        if (i>=a)
        {
            ++rest[x[i-a]];
        }
        if (i>b)
        {
            --rest[x[i-b-1]];
        }
        s+=rest[x[i]];
    }
    printf("%d\n",s);
    return 0;
}