#abc085d

N,H=map(int,raw_input().split())
a=[]
b=[]
for i in xrange(N):
 x,y=map(int,raw_input().split())
 a.append(x)
 b.append(y)
b=sorted(b,reverse=True)
amax=max(a)
cnt=0
i=0
while H>0 and i<len(b) and b[i]>amax:
 H=H-b[i]
 cnt+=1
 i+=1
if H>0:
 cnt+=(H+amax-1)/amax
print cnt
