N, H = map(int, input().split())
A = 0
B = []
ans = 0
for _ in range(N):
    a, b = map(int, input().split())
    A = max(A, a)
    B.append(b)
B.sort(reverse=True)
for i in range(N):
    if B[i] < A:
        break
    H -= B[i]
    ans += 1
if H % A == 0:
    print(ans + H // A)
else:
    print(ans + (H // A) + 1)