#include <cstdio>
#define DIM 500010
using namespace std;

int n, k, a, b;
int i, v[DIM], p[DIM], fr[DIM];
long long sol;

int main()
{

    freopen("divk.in" ,"r", stdin );
    freopen("divk.out","w", stdout);

    scanf("%d %d %d %d", &n, &k, &a, &b);

    for(i = 1; i <= n; i ++)
   {

        scanf("%d", &v[i]);
        p[i] = ( p[i-1] + v[i] ) % k;

        if(i >= a)
            fr[ p[i-a] ] ++;

        if(i > b)
            fr[ p[i-b-1] ] --;

        sol = sol + fr[ p[i] ];
    }

    printf("%lld\n", sol);

    fclose(stdin );
    fclose(stdout);

    return 0;
}