#include<bits/stdc++.h>
using namespace std;
ifstream f("divk.in");
ofstream g("divk.out");
long long n,v[500002],a,b,k,dp[500002],sol;
int main()
{
    f>>n>>k>>a>>b;
    for(int i=1;i<=n;++i)
    {
        f>>v[i];
        v[i]=(v[i-1]+v[i])%k;
        if(i>b)
            dp[v[i-b-1]]--;
        if(i>=a)
            dp[v[i-a]]++;
        sol+=dp[v[i]];
    }
    g<<sol;
    return 0;
}