import sys
input = sys.stdin.readline
N, H = map(int, input().split())

A = []
B = []
for i in range(N):
    a, b = map(int, input().split())
    A.append((a, i))
    B.append((b, i))

A.sort(reverse = True)
B.sort(reverse = True)

# print (A)
# print (B)

count = 0
b = 0
while b < N and B[b][0] > A[0][0] and H > 0:
    count += 1
    H -= B[b][0]
    b += 1

count += (H + A[0][0] - 1) // A[0][0]
print (count)
