#include <bits/stdc++.h>
using namespace std;
long long dx[4] = {1, 0, -1, 0};
long long dy[4] = {0, -1, 0, 1};
template <class T>
void inputVector(vector<T>& v, long long n) {
  v.resize(n);
  for (long long i = 0; i < v.size(); i++) cin >> v[i];
}
signed main() {
  long long N, H;
  cin >> N >> H;
  vector<long long> a(N), b(N);
  for (long long i = 0; i < (N); i++) cin >> a[i] >> b[i];
  long long maxA = *max_element((a).begin(), (a).end());
  long long ret = 0;
  sort((b).begin(), (b).end());
  reverse((b).begin(), (b).end());
  for (long long i = 0; i < (N); i++) {
    if (b[i] < maxA) break;
    H -= b[i];
    ret++;
    if (H <= 0) break;
  }
  ret += (H + maxA - 1) / maxA;
  cout << ret << endl;
  return 0;
}
