#include <bits/stdc++.h>
using namespace std;
int dp[20000];
int main() {
  long long n, m;
  scanf("%lld %lld", &n, &m);
  long long x, ara1[n + 5];
  long long a, b;
  a = b = 0;
  int ia, ib;
  for (int i = 1; i <= n; i++) {
    scanf("%lld %lld", &x, &ara1[i]);
    if (a < x) {
      a = x;
      ia = i;
    }
  }
  int ans = 0;
  bool fl = 0;
  for (int i = 1; i <= n; i++) {
    if (i == ia) {
      if (a < ara1[i]) {
        fl = 1;
        continue;
      }
    }
    if (ara1[i] > a) {
      ans++;
      m -= ara1[i];
      if (m <= 0) {
        cout << ans << endl;
        return 0;
      }
    }
  }
  if (fl) {
    ans++;
    m -= ara1[ia];
  }
  if (m > 0) {
    ans += m / a;
    if (m % a) ans++;
  }
  cout << ans << endl;
}
