#include <cstdio>
using namespace std;
int sp[500005],cnt[500005];
int main()
{
    freopen("divk.in","r",stdin);
    freopen("divk.out","w",stdout);
    int n,i,x,k,a,b;
    long long ans=0;
    scanf("%d%d%d%d",&n,&k,&a,&b);
    for(i=1;i<=n;++i)
    {
        scanf("%d",&x);
        sp[i]=(sp[i-1]+x)%k;
        if(i>b)
            cnt[sp[i-b-1]]--;
        if(i>=a)
            cnt[sp[i-a]]++;
        ans=ans+1LL*cnt[sp[i]];
    }
    printf("%lld",ans);
    return 0;
}