N,H=map(int,input().split())

a=[]
b=[]
damege=0
count=0

for i in range(N):
    A,B=map(int,input().split())
    a.append(A)
    b.append(B)

if N>1:
    b=sorted(b,reverse=True)

i=0
A=max(a)
while i<N and b[i]>A and damege<H:
    damege+=b[i]
    i+=1
    count+=1
count+=-(-max(0,H-damege)//A)

print(count)
