#include <iostream>
#include <cstdio>
#include <algorithm>
#define N 100005
using namespace std;

typedef long long ll;
ll n, h, mx, c, a, b[N];
int main()
{
	ll i;
	cin >> n >> h;
	for (i = 0; i < n; i++) scanf("%lld %lld", &a, &b[i]), mx = max(mx, a);
	sort(b, b + n);
	for (i = n - 1; i >= 0; i--) if (b[i] > mx && h > 0) h -= b[i], c++;
	if (h > 0) c += (h + mx - 1) / mx;
    cout << c << endl;
    return 0;
}