#include <bits/stdc++.h>
using namespace std;
const int INF = 1e9;
const long long INFLL = 1e18;
int dx[4] = {0, -1, 1, 0}, dy[4] = {-1, 0, 0, 1};
int main() {
  ios::sync_with_stdio(false);
  int N, H;
  cin >> N >> H;
  priority_queue<int> Q;
  int max_A = 0;
  for (int i = 0; i < (int)(N); i++) {
    int A, B;
    cin >> A >> B;
    max_A = max(A, max_A);
    Q.push(B);
  }
  int ans = 0;
  while (H > 0) {
    if (Q.size() && max_A < Q.top()) {
      H -= Q.top();
      Q.pop();
      ans++;
    } else {
      break;
    }
  }
  ans += (H + max_A - 1) / max_A;
  cout << ans << endl;
}
