N, H = [int(i) for i in input().split()]
L = [[int(i) for i in input().split()] for _ in range(N)]
A = max(a for a, _ in L)
B = sorted(b for a, b in L if b > A)
M = len(B)
while B and H > 0:
    H -= B.pop()
print(M - len(B) + max(-1, H - 1) // A + 1)