#include <bits/stdc++.h>
using namespace std;
const long long INFL = 1e18;
const int INF = 1001001001;
const int mod = 1000000007;
int main() {
  long long n, h;
  cin >> n >> h;
  vector<int> B;
  long long ma = 0, pb = 0;
  for (int(i) = 0; (i) < (n); (i)++) {
    long long a, b;
    cin >> a >> b;
    ma = max(ma, a);
    B.push_back(b);
  }
  sort((B).begin(), (B).end(), greater<int>());
  long long ans = 0;
  for (int(i) = 0; (i) < (n); (i)++) {
    if (B[i] <= ma) break;
    h -= B[i];
    ans++;
  }
  while (h > 0) {
    h -= ma;
    ans++;
  }
  cout << ans << endl;
}
