# -*- coding: utf-8 -*-
import sys
import math

def main():
    text = sys.stdin.readline()
    biscuits_n =  int(text)

    biscuits_inp = 1
    biscuits_outp = 0
    biscuits_total = biscuits_inp + biscuits_outp
    tap_count = 0
    tap_total = 0
    
    while biscuits_n > biscuits_total:
        #ポケットをたたく回数算出
        if (biscuits_n - biscuits_total) == 1:
            tap_count = 1
        else:
            tap_count = math.floor((math.log10(biscuits_n - biscuits_outp) - math.log10(biscuits_inp)) / math.log10(2))
        tap_total +=  tap_count
        
        #"ビスケットを増やす"
        biscuits_inp = pow(biscuits_inp * 2,tap_count)
        biscuits_total = biscuits_inp + biscuits_outp
        
        #ビスケットをポケットの外に出す
        biscuits_outp += biscuits_inp
        biscuits_inp = 0
        
        #増やすビスケットをポッケの中に戻す
        if (biscuits_n - biscuits_total) == 1.0 :
            biscuits_inp = 1.0
        else:
            biscuits_inp = math.floor(biscuits_n - biscuits_outp)
        biscuits_outp -= biscuits_inp
        
        #print("tap:" + str(tap_count),"total biscuits:" + str(biscuits_total),"outside poket:" + str(biscuits_outp),"inside poket:" + str(biscuits_inp))
        
    print(tap_total)
    
if __name__ == "__main__":
    main()