# coding: utf-8
# Your code here!
n,H=map(int,input().split())
S=[]
for i in range(n):
    
    S.append(list(map(int,input().split())))
    
a=[]
b=[]
for i in range(n):
    a.append(S[i][0])
    
for i in range(n):
    if(max(a)<S[i][1]):
        b.append(S[i][1])

b.sort()
b.reverse()
k=0
count=0
while H>0:
    if len(b)>k:
        H-=b[k]
        k+=1
        count+=1
    else:
        
        count+=H//max(a)
        H=0

print(count)
