#include <bits/stdc++.h>
using namespace std;
const long long LLINF = 9223372036854775807;
const int MOD = 1000000007;
int main() {
  long long N, H;
  cin >> N >> H;
  long long a[N], b[N];
  for (int i = 0; i < (int)N; i++) cin >> a[i] >> b[i];
  sort(a, a + N, greater<int>());
  sort(b, b + N, greater<int>());
  long long result = 0;
  for (int i = 0; i < (int)N; i++) {
    if (b[i] <= a[0]) break;
    result++;
    H -= b[i];
    if (H <= 0) break;
  }
  result += ceil((float)H / a[0]);
  cout << result << endl;
  return 0;
}
