import math
N, H = map(int, input().split())
A = [0] * N
B = [0] * N
for i in range(N):
    a, b = map(int, input().split())
    A[i] = a
    B[i] = b

B.sort(reverse=True)
def calc():
    maxa = max(A)
    cnt = 0
    h = H
    # 最後に投げるやつを計算
    for b in B:
        if maxa < b:
            cnt += 1
            h -= b
        if h < 0:
            return cnt

    # 投げて倒せるまでmaxaで切り続ける
    cnt += math.ceil(h/maxa)
    return cnt

print(int(calc()))
