#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, h;
  cin >> n >> h;
  int maxstrike = 0, sum = 0;
  int a[n + 10];
  for (int i = 0; i < n; i++) {
    int strike, throww;
    cin >> strike >> throww;
    if (strike > maxstrike) maxstrike = strike;
    a[i] = throww;
  }
  int c = 0;
  for (int i = 0; i < n; i++) {
    if (a[i] > maxstrike) {
      sum += a[i];
      c++;
    }
    if (sum >= h) break;
  }
  if (sum < h) {
    int x = h - sum;
    int y = x / maxstrike;
    if (x % maxstrike != 0) y++;
    c += y;
  }
  cout << c;
}
