#include <cstdio>
using namespace std;
long long a,b,k,n,s,i,v[500201],t[500201];
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",&v[i]);
        v[i]=(v[i-1]+v[i])%k;
    }
    for(i=a;i<=n;++i)
    {
        ++t[v[i-a]];
        if(i>b) --t[v[i-b-1]];
        s+=t[v[i]];
    }
    printf("%lld",s);
    return 0;
}