#include<stdio.h>
#include<math.h>

int main (){
    int N;
    int i = 0,p;
    scanf("%d",&N);
    
    for(i = 0; 1 <= N/2; i++){
        if(1 == N%2) N++;
        N = N / 2;    
    }
    printf("%d",i);
}