import numpy as np

n, h = map(int, input().split())
a = 0
b = []
for i in range(n):
    A, B = map(int, input().split())
    a = max(a, A)
    b.append(B)
b = np.array(b, dtype=np.int64)
b = np.sort(b[b > a])[::-1]

if b.sum() >= h:
    cnt = 0
    for i in b:
        h -= b
        cnt += 1
        if h < 0:
            print(cnt)
            exit()

print((h - b.sum() + a - 1) // a + len(b))