N, H = map(int, input().split())
A = [0]*N
B = [0]*N
for i in range(N):
    A[i], B[i] = map(int, input().split())
A.sort()
B.sort()
ans = 0
while len(B) > 0 and B[-1] >= A[-1] and H > 0:
    H -= B.pop()
    ans += 1
print(ans+(-(-H//A[-1])))