N,H = map(int,input().split())
A,B = [],[]
for i in range(N):
    a,b = map(int,input().split())
    A.append(a)
    B.append(b)
B.sort(reverse=True)
a = max(A)
ans = 0
for b in B:
    if a<b:
        H-=b
    else:
        H-=a
    ans+=1
    if H<=0:break
print(ans if H<=0 else ans+H//a if H%a==0 else ans+H//a+1)