N,H=map(int,input().split(' '))
A=0
B=[]
ans = 0
for i in range(N):
    a,b=map(int,input().split(' '))
    A=max(a,A)
    B.append(b)
B=sorted([i for i in B if i > A],reverse=True)
for i in B:
    H -=i
    ans += 1
    if H<=0:
        print(ans)
        exit()
ans+=-((-1*H)//A)
print(ans)