def main():
    N = int(input())
    hit = 0
    biscuit = 1

    while biscuit * 2 <= N:
        biscuit = biscuit * 2
        hit += 1
    
    while (N - biscuit) > 0:
        biscuit += (N - biscuit) * 2
        hit += 1

    print(hit)

if __name__ == '__main__':
    main()