/* -*- coding: utf-8 -*-
 *
 * 3252.cc:  No.3252 Constrained Moving - yukicoder
 */

#include<cstdio>
#include<algorithm>

using namespace std;

/* constant */

const int MAX_N = 200000;

/* typedef */

/* global variables */

int as[MAX_N];

/* subroutines */

/* main */

int main() {
  int n, s, t, k;
  scanf("%d%d%d%d", &n, &s, &t, &k);
  s--, t--;
  for (int i = 0; i < n; i++) scanf("%d", as + i);

  if (as[s] + as[t] <= k) puts("1");
  else {
    int mina = *min_element(as, as + n);
    if (as[s] + mina <= k && mina + as[t] <= k)
      puts("2");
    else
      puts("-1");
  }

  return 0;
}