#include <cstdio>
using namespace std;
const int NMAX = 500000;
int v[NMAX + 5];
int ap[NMAX + 5];
int main()
{
    freopen("divk.in", "r", stdin);
    freopen("divk.out", "w", stdout);
    int n, t, d, a, b, k;
    long long s = 0;
    scanf("%d %d %d %d", &n, &k, &a, &b);

    for(register int i = 1; i <= n; ++i )
    {
        scanf("%d", &t);
        v[i] = ( v[i - 1] + t ) % k; /// practic suma de la 1 la i (restul)
        if( i >= a )
            ++ap[v[i - a]]; /// crestem de cate ori a aparut restul
        if( i > b )
            --ap[v[i - b - 1]]; /// scadem pt ca l > b;
        s += ap[v[i]];

    }
    printf("%lld", s);
    return 0;
}