import math
N, H = list(map(int, input().split()))
AB = [list(map(int, input().split())) for _ in range(N)]

a_max = max(a for a,b in AB)
B = [b for a,b in AB]
B.sort(reverse=True)

HP = H
ans =0
for b in B:
    if HP<0:
        print(ans)
        exit()
    if b<a_max:
        break
    HP -=b
    ans+=1

#ans += HP//a_max+ bool(HP%a_max)
ans += math.ceil(HP/a_max)
print(ans)