n,h =map(int,input().split())
a,b = [0]*n,[0]*n
for i in range(n):
    a[i],b[i] = map(int,input().split())
A = max(a)
s = set()
for i in range(n):
    if b[i] > A:
        s.add(b[i])
s = list(s)
s.sort()
s.reverse()
c = sum(s)
if c < h:
    print(len(s) + (h-c)//A + [1,0][(h-c)%A==0])
else:
    for i in range(len(s)):
        if sum(s[:i+1]) > h:
            print(i+1)
            break