from math import ceil
N, H = map(int, input().split())
A, B = 0, []
for i in range(N):
    a, b = map(int, input().split())
    A = max(A, a)
    B.append(b)

B = [b for b in B if b > A]
B.sort()

ans = 0
while H > 0 and B:
    ans += 1
    H -= B.pop()

H = max(0, H)
ans += ceil(H / A)
print(ans)
