#include <fstream>
#define int long long
using namespace std;
ifstream cin("divk.in");
ofstream cout("divk.out");
const int maxn=5e5+5;
int s[maxn];
int f[100005];
int n,k,a,b;
int32_t main()
{
    cin>>n>>k>>a>>b;
    for(int i=1;i<=n;i++){
        int x;
        cin>>x;
        s[i]=(s[i-1]+x)%k;
    }
    int cnt=0;
    for(int j=a;j<=n;j++){
        f[s[j-a]]++;
        cnt+=f[s[j]];
        if(j-b>=0) f[s[j-b]]--;
    }
    cout<<cnt;
    return 0;
}