#include <bits/stdc++.h>
using namespace std;
const int INF = (int)1e9;
const long long IINF = 1LL << 62;
const int maxn = 10000005;
long long modexpo(long long a, long long b) {
  long long res = 1LL;
  while (b > 0) {
    if (b & 1) res = (res * a) % 1000000007;
    a = (a * a) % 1000000007;
    b >>= 1;
  }
  return res;
}
int main() {
  long long n, h;
  cin >> n >> h;
  long long k[n];
  long long mx = 0;
  for (int i = 0; i < n; i++) {
    long long x, y;
    cin >> x >> y;
    mx = max(mx, x);
    k[i] = y;
  }
  sort(k, k + n);
  reverse(k, k + n);
  long long ct = 0;
  int i = 0;
  while (i < n) {
    long long t = (h + mx - 1) / mx;
    long long t2 = 1 + (h - k[i] + mx - 1) / mx;
    if (t2 <= t) {
      ct++;
      h -= k[i];
      i++;
    } else {
      break;
    }
  }
  if (h > 0) ct += (h + mx - 1) / mx;
  cout << ct;
}
