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)

maxa=max(A)
C=[]
B.sort(reverse=True)
ans=0
for ele in B:
    if ele<maxa:
        break
    ans+=1
    h-=ele
    if h<=0:
        break
ans+=(h+maxa-1)//maxa
print(ans)