#include<iostream>
using namespace std;
bool a[10] = {0, 0, 0, 0, 0, 0, 0, 1, 0, 0};
int main(){
    ios::sync_with_stdio(false);
    int n, ii = 0;
    cin >> n;
    if(n < 0){
        a[7] = 0;
        n = (-1)*n;
    }
    n--;
    while(n != 0){
        a[ii++] = (n & 1);
        n = n >> 1;
    }
    for(int i = 0; i <= 7; i++){
        if(!a[i]){
            cout << i;
            return 0;
        }
    }
    return 0;
}