#include <bits/stdc++.h>
#define int long long
using namespace std;
ifstream fin("divk.in");
ofstream fout("divk.out");
int sp[500001];
int freq[100001];
signed main()
{
    int n,k,a,b,x,ans=0;
    fin>>n>>k>>a>>b;
    for(int i=1;i<=n;i++)
    {
        fin>>x;
        sp[i]=(sp[i-1]+x)%k;
    }
    for(int i=a;i<=n;i++)
    {
        freq[sp[i-a]]++;
        ans+=freq[sp[i]];
        if(i>=b) freq[sp[i-b]]--;
    }
    fout<<ans;
    return 0;
}