import math
N,H = map(int,input().split())
A,B = [],[]
for i in range(N):
    a,b = map(int,input().split())
    A.append(a)
    B.append(b)
A.sort(reverse=True)
B.sort(reverse=True)
i,p = 0,0
while i<N and A[0]<=B[i]:
    p += B[i]
    i += 1
ans = math.ceil((H-p)/A[0])
print(ans+i)
