#include <bits/stdc++.h>
using namespace std;
using ll = long long;
int dx[4] = {0, 1, 0, -1};
int dy[4] = {1, 0, -1, 0};
int main() {
  ll n, h;
  cin >> n >> h;
  ll a[n], b[n];
  ll mx_a = 0;
  vector<ll> v(0);
  ll sum_b = 0;
  for (ll i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    mx_a = max(mx_a, a[i]);
  }
  for (ll i = 0; i < n; i++) {
    if (b[i] >= mx_a) {
      v.push_back(b[i]);
      sum_b += b[i];
    }
  }
  ll ans = 0;
  ans += v.size();
  h -= sum_b;
  if (h % mx_a == 0) {
    ans += (h / mx_a);
  } else {
    ans += (h / mx_a) + 1;
  }
  cout << ans << endl;
}
