from math import ceil
n, h = map(int, input().split())
a = [0] * n
b = [0] * n
for i in range(n):
    a[i], b[i] = map(int, input().split())
b.sort()
b.reverse()
cnt = 0
ma = max(a)
for i in range(n):
    if b[i] > ma:
        h -= b[i]
        cnt += 1
    if h <= 0:
        print(cnt)
        exit()
cnt += ceil(h / ma)
print(cnt)