#include<stdio.h>

int main(){
	long N, H;
	scanf("%ld %ld", &N, &H);
	long a[100001], b[100001];
	long a_max = 0;
	for (long i = 0; i < N; i++) {
		scanf("%ld %ld", &a[i], &b[i]);
		if (a[i] > a_max) {
			a_max = a[i];
		}
	}

	long ans = 0;
	long D = 0;

	for (long i = 0; i < N; i++) {
		if (a_max < b[i]) {
			D += b[i];
			ans++;
			if (D >= H) {
				printf("%ld\n", ans);
				return 0;
			}
		}
	}

	
	if (D >= H) {
		ans += (H - D) / a_max;
		printf("%ld\n", ans);
		break;
	}

	return 0;

}