#include <bits/stdc++.h>
using namespace std;
static const long long maxLL = (long long)1 << 62;
const int mod = 1000000007;
int dy[] = {-1, 0, 1, 0};
int dx[] = {0, 1, 0, -1};
long long n, h;
long long a[100010], b[100010];
long long maxa = 0;
signed main() {
  cin >> n >> h;
  for (long long i = 0; i < n; i++) {
    cin >> a[i] >> b[i];
    if (maxa < a[i]) maxa = a[i];
  }
  long long cnt = 0;
  for (long long i = 0; i < n; i++) {
    if (maxa < b[i]) h -= b[i], cnt++;
  }
  cnt += h / maxa + (h % maxa ? 1 : 0);
  cout << cnt << endl;
  return 0;
}
