import math
n,h=map(int,input().split())
cnt=0
ans=0
m=0
b=[]
for i in range(n):
    a,B=map(int,input().split())
    b.append(B)
    if m<a:
        m=a
b=sorted(b,reverse=True)
for i in range(len(b)):
    if b[i]<m:
        break
    else:
        cnt+=b[i]
        ans=i+1
print(ans+math.ceil((h-cnt)/m))








