n,h = map(int,input().split())
A = []
B = []

for i in range(1,n+1):
    a,b = map(int,input().split())
    A.append(a)
    B.append(b)
amax = max(A)

B = list(filter(lambda x: x > amax, B))
B.sort()
ans = 0
while h >0:
    if B:
        h -= B.pop()
    else:
        ans += math.ceil(h/amax)
        break
    ans += 1
print(ans)