#include <bits/stdc++.h>
using namespace std;
int main() {
  int N;
  cin >> N;
  long long H;
  cin >> H;
  long long A[100010], B[100010];
  for (int i = 0; i < N; i++) cin >> A[i] >> B[i];
  sort(A, A + N, greater<long long>());
  sort(B, B + N, greater<long long>());
  long long sum = 0;
  for (int i = 0; i < N; i++) {
    if (A[0] > B[i]) continue;
    sum += B[i];
    if (sum >= H) {
      cout << i + 1 << endl;
      break;
    }
  }
  if (sum >= H)
    ;
  else if ((H - sum) % A[0] == 0)
    cout << (H - sum) / A[0] << endl;
  else {
    cout << (H - sum) / A[0] + 1 << endl;
  }
}
