#include <bits/stdc++.h>
#define ull unsigned long long
using namespace std;

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

int n, k, a, b;
ull v[100005], ans;
int vf[500005];

int main()
{
    int x;
    f >> n >> k >> a >> b;
    for( int i = 1; i <= n; ++i)
    {
        f >> x;
        v[i] = v[i - 1] + (ull)x;
        if( i - a >= 0 )
            ++vf[ v[i - a] % k ];
        if( i - b -1 >= 0 )
            --vf[ v[i - b - 1] % k];
        if( i - a >= 0)
            ans += vf[ v[i] % k ];
    }
    g << ans;
    return 0;
}