n,h = (int(i) for i in input().split())
x = [[int(i) for i in input().split()] for i in range(n)]
a,b = 0,[]
for j in x:
	if a < j[0]: a = j[0]
	b.append(j[1])
num = 0
b.sort().reverse()
for j2 in b:
	if j2 >=a and h>0: 
	    h -= j2
		num +=1
	else: break
if h<=0: print(num)
else:
	if h%a==0: print((h-h%a)//a + num)
	else: print((h-h%a)//a + num + 1)