#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using vi = vector<int>;
using vvi = vector<vi>;
using vvvi = vector<vvi>;
using vl = vector<ll>;
using vvl = vector<vl>;
using vvvl = vector<vvl>;
using vd = vector<double>;
using vvd = vector<vd>;
using vb = vector<bool>;
using vvb = vector<vb>;
using vs = vector<string>;
const int INF = (1 << 30) - 1;
const ll INF64 = ((ll)1 << 62) - 1;
const double PI = 3.1415926535897932384626433832795;
const int dx[] = {-1, 0, 1, 0};
const int dy[] = {0, 1, 0, -1};
int gcd(int x, int y) { return y ? gcd(y, x % y) : x; }
ll gcd(ll x, ll y) { return y ? gcd(y, x % y) : x; }
int lcm(int x, int y) { return x / gcd(x, y) * y; }
ll lcm(ll x, ll y) { return x / gcd(x, y) * y; }
int solve(int n, int h, vector<int> a, vector<int> b) {
  int ma = 0;
  for (int i = 0; i < n; i++) {
    ma = max(ma, a[i]);
  }
  int cnt = 0;
  for (int i = 0; i < n; i++) {
    if (ma < b[i]) {
      h -= b[i];
      cnt++;
    }
    if (h <= 0) {
      return cnt;
    }
  }
  cnt += h / ma;
  cnt += (bool)(h % ma);
  return cnt;
}
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, h;
  cin >> n >> h;
  vector<int> a(n), b(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
  }
  cout << solve(n, h, a, b) << endl;
  return 0;
}
