#include <bits/stdc++.h>

using namespace std;

ifstream f("divk.in");
ofstream g("divk.out");

int N,K,A,B;
int S[500001],V[100001];

int main()
{
    f>>N>>K>>A>>B;
    for(int i=1,x;i<=N;i++)
    {
        f>>x;
        S[i]=(x+S[i-1])%K;
    }
    uint64_t result=0;
    for(int i=1;i<=N;i++)
    {
        if(i>=A)   V[S[i-A]]++;
        if(i>=B+1) V[S[i-(B+1)]]--;
        result+=V[S[i]];
    }
    g<<result;

    return 0;
}