#include <bits/stdc++.h>
using namespace std;
int n, m;
string s;
int a[100001], b[100001];
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.precision(10);
  cout << fixed;
  cin >> n >> m;
  int maxa = 0;
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    maxa = max(maxa, a[i]);
  }
  long long ans = 0;
  for (int i = 0; i < n; i++) {
    if (m <= 0) break;
    if (b[i] >= maxa) {
      m -= b[i];
      ans++;
    }
  }
  if (m > 0) ans += m / maxa;
  if (m % maxa != 0 && m > 0) ans++;
  cout << ans << endl;
  return 0;
}
