#include <bits/stdc++.h>
using namespace std;
bool cmp(long long a, long long b) { return a > b; }
int main() {
  long long a[100005];
  long long b[100005];
  long long N, H;
  long long x = 0;
  cin >> N >> H;
  long long bsum = 0;
  long long aindex;
  long long amax = 0, bmax = 0;
  for (long long i = 0; i < N; i++) {
    cin >> a[i] >> b[i];
    bsum += b[i];
    if (a[i] > amax) {
      aindex = i;
      amax = a[i];
    }
  }
  long long i;
  int flag = 0;
  for (i = 0; i < N; i++) {
    if (b[i] > amax) {
      if (i == aindex) {
        flag = 1;
        continue;
      }
      H -= b[i];
      x++;
    }
  }
  while (H > 0) {
    if (flag == 0) {
      H -= amax;
      x++;
    } else {
      if (H - b[aindex] <= 0) {
        x++;
        break;
      }
      H -= amax;
      x++;
    }
  }
  cout << x << endl;
  return 0;
}
