#include <bits/stdc++.h>
using namespace std;
const long long MOD = 1000000007;
const int N = 500000 + 10;
long long n, h;
long long a[N], b[N];
set<long long> st_b, st_a;
bool cmp(long long x, long long y) { return x > y; }
int main() {
  scanf("%lld %lld", &n, &h);
  for (int i = (1); i <= (n); i++) {
    scanf("%lld %lld", &a[i], &b[i]);
    st_a.insert(a[i]);
    st_b.insert(b[i]);
  }
  long long mx_a = *st_a.rbegin();
  long long ans = 1e9 + 7;
  sort(b + 1, b + 1 + n, cmp);
  long long sum = 0;
  for (int i = (0); i <= (n); i++) {
    sum += b[i];
    if (sum > b[i]) break;
    long long tmp = ((h - sum) + mx_a - 1) / mx_a + i;
    ans = min(ans, tmp);
  }
  cout << ans << endl;
}
