from operator import itemgetter
N, H = map(int, input().split())
b = []
a = []
for i in range(N):
    n, m = map(int, input().split())
    b.append(m)
    a.append(n)
a_max = max(a)
ans = 0
b.sort(reverse = True)
for i in range(N):
    if b[i] > a_max:
        H -= b[i]
        ans += 1
        if i == N-1:
            ans += 1 + (H-1) // a_max

    else:
        ans += 1 + (H-1) // a_max
        break
print(ans)
