N,H = map(int,input().split())
A = []
B = []
for i in range(N):
    a,b = map(int,input().split())
    A.append(a)
    B.append(b)

maxA = max(A)

ans = 0
B.sort(reverse=True)
for i in range(N):
    if B[i] <= maxA: break
    H -= B[i]
    ans += 1

from math import ceil
ans += ceil(H/maxA)

print(ans)