#include <fstream>
using namespace std;
int n,k,a,b,v[500002],i,dp[100001];
long long ct;
ifstream f("divk.in");
ofstream g("divk.out");
int main()
{
    f>>n>>k>>a>>b;
    for(i=1;i<=n;i++)
    {
        f>>v[i];
        v[i]=(v[i]+v[i-1])%k;
        if(i>b)
        {
            dp[v[i-b-1]]--;
        }
        if(i>=a)
        {
            dp[v[i-a]]++;

        }
        ct=ct+dp[v[i]];
    }
    g<<ct;
    return 0;
}