《新符号，-->》

#include<stdio.h>
#include<string>
std::string pal(std::string s){
    std::string s_pal;
    for(int i=s.size();i-->0;)s_pal+=s[i];
    return s_pal;
}
int main(){
    int n;
    scanf("%d",&n);
    std::string nb;
    while(n){
        nb+=(n%2)+'0';
        n/=2;
    }
    nb=pal(nb);
    int ans=nb.size()-1;
    for(int i=nb.size();i-->0;){
        if(nb[i]=='1')break;
        ans--;
    }
    printf("%d",ans);
}