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).sort()).reverse()
c = sum(s)
if c < h:
    print((h-c)//A + [1,0][(h-c)%A==0])
else:
    cnt = 0
    l = 0
    for i in range(len(s)):
        cnt += s[i]
        l += 1
        if cnt >= h:
            break
    print(l)