import math
N = int(input())
A = math.log(N)
B = math.log(2)
def is_integer_num(n) :
    if isinstance(n, int) :
        return True
    if isinstance(n, float) :
        return n.is_integer()
    return False
if is_integer_num(A / B)  :
    print(int(A / B))
else :
    print(math.floor(A / B) + 1)