#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1e9 + 7;
const int inf = 1e9;
const long long INF = 1e18;
const double pi = 3.14159265358979323846;
int main() {
  int n;
  long long h;
  cin >> n >> h;
  long long a[n], b[n], mx = 0;
  for (long long i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    mx = max(mx, a[i]);
  }
  long long ans = 0;
  for (long long i = 0; i < n; i++) {
    if (mx > b[i])
      continue;
    else {
      h -= b[i];
      ans++;
      if (h <= 0) break;
    }
  }
  if (h > 0) ans += (ceil)((double)h / mx);
  cout << ans << "\n";
}
