n, h = map(int, input().split())
AB = [(list(map(int, input().split()))) for _ in range(n)]

A = []
B = []
for a, b in AB:
    A.append(a)
    B.append(b)

max_A = max(A)
C = [b for b in B if b >= max_A]
sum_C = sum(C)
ans = len(C)
if sum_C >= h:
    print(ans)
else:
    h -= sum_C
    atack = h // max_A
    ans += atack
    h -= atack * max_A
    if h <= 0:
        print(ans)
    else:
        print(ans+1)