#include <bits/stdc++.h>
using namespace std;
long long Power(long long a, long long b) {
  long long result = 1;
  while (b) {
    if (b % 2) {
      result = (result * a) % 1000000007LL;
    }
    b = b >> 1;
    a = (a * a) % 1000000007LL;
  }
  return result;
}
int main() {
  std::ios_base::sync_with_stdio(false);
  long long N, i, H, Sum = 0;
  cin >> N >> H;
  vector<long long> a(N), b(N);
  for (i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
  }
  long long Max = *max_element(a.begin(), a.end());
  long long Ans1 = H / Max;
  long long cnt = 0LL;
  for (i = 0; i < N; i++) {
    if (b[i] > Max) {
      H -= b[i];
      cnt++;
    }
    if (H <= 0LL) {
      cout << cnt;
      exit(0);
    }
  }
  long long Ans = cnt + ceil(H * 1.0 / Max);
  cout << Ans;
  return 0;
}
