import java.util.Arrays;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int h = sc.nextInt();
		int[] a = new int[n];
		int[] b = new int[n];
		int sum = 0;

		if (n >= 1 && n <= 100000 && h >= 1 && h <= 1000000000) {
			for (int i = 0; i < n; i++) {
				a[i] = sc.nextInt();
				b[i] = sc.nextInt();
				if (a[i] > b[i]) {
					return;
				}
				sum = sum + b[i];
			}

			Arrays.sort(a);
			Arrays.sort(b);
			if (b[0] >= a[n - 1]) {
				if (sum >= h) {
					int tmp = 0;
					for (int i = 0; i < n; i++) {
						tmp = sum - b[i];
						if (tmp >= h) {
							sum = tmp;
						} else {
							System.out.println(n - i);
							return;
						}
					}
				} else {
					int tmp = h - sum;
					int t = tmp / a[n - 1];
					if (tmp <= (a[n - 1] * t)) {
						System.out.println(n + t);
						return;
					} else {
						System.out.println(n + t + 1);
						return;
					}

				}

			} else {
				int r = 0;
				for (int i = 0; i < n; i++) {
					if (b[i] <= a[n - 1]) {
						sum = sum - b[i];
						r = r + 1;
					}
				}

				int tmp = h - sum;
				int t = tmp / a[n - 1];
				if (tmp <= (a[n - 1] * t)) {
					System.out.println(n + t - r);
					return;
				} else {
					System.out.println(n + t + 1 - r);
					return;
				}
			}

		}

	}
}
