
def main():
    N, H = list(map(int, input().split()))
    a_max = 0
    b_list = []

    for _ in range(N):
        a,b = list(map(int, input().split()))
        a_max = max(a, a_max)
        b_list.append(b)

    b_list = sorted(b_list)[::-1]
    
    cnt = 0
    while H > 0:
        H -= b_list.pop(0) if len(b_list) > 0 and b_list[0] > a_max else a_max
        cnt += 1
    print(cnt)

if __name__ == "__main__":
    main()
