N = int(raw_input())
biscuit = 2
times = 1
if N == 1:
    print "0"
else:
    while True:
        if biscuit * 2 < N:
            biscuit *= 2
            times += 1
        else:
            break
    if N == biscuit:
        print times
    else:
        times += 1
        print times