n , h = map(int,input().split())
p = []
q = []
for i in range(n):
    a , b = map(int,input().split())
    p.append(a)
    q.append(b)
A = max(p)
q.sort(reverse=True)
ans = 0
for i in range(n):
    ans += 1
    h -= max(q[i],A)
    if h <= 0:
        print(ans)
        exit()

ans += -(-h//A)
print(ans)