#include <bits/stdc++.h>
using namespace std;
int N;
long long H;
vector<int> thrower;
int a[100001];
int b[100001];
int main(void) {
  cin >> N >> H;
  for (int i = 1; i < N + 1; i++) {
    cin >> a[i] >> b[i];
  }
  int ma = 0;
  for (int i = 1; i < N + 1; i++) {
    ma = max(ma, a[i]);
  }
  for (int i = 1; i < N + 1; i++) {
    if (b[i] > ma) thrower.push_back(b[i]);
  }
  sort(thrower.begin(), thrower.end());
  int ans = 0;
  for (int x : thrower) {
    ans++;
    H -= x;
    if (H <= 0) {
      cout << ans << endl;
      return 0;
    }
  }
  ans += (H + ma - 1) / ma;
  cout << ans << endl;
}
