#include <cstdio>
#include <algorithm>
using namespace std;
int n, h, a, b[100005], ma, ans;
int main() {
    int i;
    scanf("%d%d", &n, &h);
    for (i=0; i<n; i++) {
        scanf("%d%d", &a, &b[i]);
        ma = max(ma, a);
    }
    sort(b, b+n);
    for (i=n-1; i>=0 && h>0; i--) {
        ans++;
        h -= max(b[i], ma);
    }
    if (h>0) ans += (h+ma-1) / ma;
    printf("%d", ans);
    return 0;
}