#include <cstdio>
#include <vector>
#define MAX 100000
using namespace std;
int vc[MAX+1], v[500001];
int main()
{
    freopen("divk.in", "r", stdin);
    freopen("divk.out", "w", stdout);
    int n, k,a,b, i, s=0,  x;
    long long r=0;
    scanf("%d%d%d%d", &n, &k, &a, &b);
    for(i=1;i<=n;i++)
    {
        scanf("%d", &x);
        s=(s+x)%k;
        v[i]=s;
    }
    for(i=a;i<=n;i++)
    {
        vc[v[i-a]]++;
        r+=vc[v[i]];
        if(i>b)
            vc[v[i-b-1]]--;
    }
    printf("%lld", r);
    return 0;
}