#include <bits/stdc++.h>
int main() {
  int m, n, t = 0, a[100000], b[100000], max, m1, s = 0, i, m2;
  scanf("%d%d", &n, &m);
  for (i = 0; i < n; i++) scanf("%d%d", &a[i], &b[i]);
  max = a[0];
  for (i = 1; i < n; i++)
    if (a[i] > max) max = a[i];
  while (m > 0) {
    for (i = 0; i < n; i++)
      if (b[i] != 0) break;
    m1 = b[i];
    m2 = i;
    for (; i < n; i++)
      if (b[i] > m1) {
        m1 = b[i];
        m2 = i;
      }
    if (m1 > max) {
      m -= m1;
      b[m2] = 0;
      s++;
    } else
      break;
  }
  if (m > 0) t = m / max + 1 - (m % max == 0);
  printf("%d", s + t);
  return 0;
}
