n,h = map(int,input().split())
x = []
for i in range(n):
	x.append(list(map(int,input().split())))
a = []
for i in range(n):
	a.append(x[i][0])
b = []
for i in range(n):
	b.append(x[i][1])
c = []

for i in range(n):
	if b[i]>max(a)-1:
			c.append(b[i])
h -=sum(c)
q = h//max(a)
print(q+len(c))