#include <cstdio>
#define MAX 100000
using namespace std;
int vc[MAX+10], v[500010];
int main()
{
    freopen("divk.in", "r", stdin);
    freopen("divk.out", "w", stdout);
    long long n, k,a,b, i,  x;
    long long r=0;
    scanf("%lld%lld%lld%lld", &n, &k, &a, &b);
    for(i=1;i<=n;i++)
    {
        scanf("%lld", &x);
        v[i]=(v[i-1]+x)%k;
    }
    for(i=a;i<=n;i++)
    {
        vc[v[i-a]]++;
        r=r+vc[v[i]];
        if(i>=b)
            vc[v[i-b]]--;
    }
    printf("%lld", r);
    return 0;
}