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())
ma = max(a)
b.sort(reverse=True)
ans = 0
index = 0
while H > 0 and len(b) > index and b[index] > ma:
    H -= b[index]
    index += 1
    ans += 1
if H > 0:
    ans += (H + ma - 1) // ma
print(ans)
