#include <bits/stdc++.h>
using namespace std;
const int INF = 1001001001;
const long long LINF = 1001001001001001001ll;
const int MOD = 1000000007;
template <class T>
inline bool chmin(T& a, T b) {
  if (a > b) {
    a = b;
    return true;
  }
  return false;
}
template <class T>
inline bool chmax(T& a, T b) {
  if (a < b) {
    a = b;
    return true;
  }
  return false;
}
int main() {
  long long N, H;
  cin >> N >> H;
  vector<long long> a(N), b(N);
  for (int i = 0; i < (N); ++i) cin >> a[i] >> b[i];
  long long max_a = 0;
  for (int i = 0; i < (N); ++i) {
    chmax(max_a, a[i]);
  }
  long long ans = 0;
  for (int i = 0; i < (N); ++i) {
    if (b[i] < max_a) continue;
    ans++;
    H -= b[i];
    if (H <= 0) {
      cout << ans << endl;
      return 0;
    }
  }
  ans += (H + max_a - 1) / max_a;
  cout << ans << endl;
}
