import sys
import math
sys.setrecursionlimit(10 ** 7)
f_inf = float('inf')
mod = 10 ** 9 + 7


def resolve():
    n, h = map(int, input().split())
    A, B = [], []
    for _ in range(n):
        a, b = map(int, input().split())
        A.append(a)
        B.append(b)
    max_a = max(A)
    res = 0
    for i in range(n):
        if B[i] > max_a:
            h -= B[i]
            res += 1
        if h <= 0:
            break

    res += math.ceil(h / max_a)
    print(res)


if __name__ == '__main__':
    resolve()
