#include <bits/stdc++.h>
using namespace std;
int main() {
  int i, check;
  long long a, b, m, m2, N, H, sum;
  m = 1;
  m2 = 1000000000;
  sum = 1;
  vector<long long> B;
  cin >> N, cin >> H;
  for (i = 0; i < N; i++) {
    cin >> a, cin >> b;
    if (a == m) {
      if (b < m2) {
        m2 = b;
        check = i;
      }
    } else if (a > m) {
      m = a;
      m2 = b;
      check = i;
    }
    B.push_back(b);
  }
  B[check] = 0;
  i = 0;
  sort(B.begin(), B.end(), greater<long long>());
  while (H > m2) {
    if (B[i] > m) {
      H -= B[i];
      sum++;
    } else if (B[i] <= m) {
      sum += (H - m2) / m;
      if ((H - m2) % m != 0) sum += 1;
      H = 0;
    }
    i++;
  }
  cout << sum << endl;
  return 0;
}
