def resolve():
    '''
    code here
    '''
    N, H = [int(item) for item in input().split()]
    ab = [[int(item) for item in input().split()] for _ in range(N)]
    ab.sort(reverse=True, key=lambda x:x[1])
    a_max_ab = max(ab, key=lambda x:x[0])

    cnt = 0    
    for a, b in ab:
        if b > a_max_ab[0]:
            H -= b
            cnt += 1
        
        if H <= 0:
            break


    cnt += H // a_max_ab[0]
    if H  % a_max_ab[0] != 0:
        cnt += 1

    print(cnt)


if __name__ == "__main__":
    resolve()
