#include <bits/stdc++.h>
using namespace std;
int n,k,a,b,i,s[50010],v[50010];
long long ans;
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",&s[i]);
        s[i]+=s[i-1];
        s[i]%=k;
    }
    for(i=a; i<=n; ++i)
    {
        v[s[i-a]]++;
        if(i>b)v[s[i-b-1]]--;
        ans+=v[s[i]];
    }
    printf("%lld\n",ans);
    return 0;
}