#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int f(int n) {
    vector<int> v(n);
    for(int i = 0; i < n; i++) {
        v[i] = i + 1;
    }
    int mile = 1;
    while((int) v.size() > 1) {
        int cnt = 1;
        vector<int> tmp;
        if(mile == 1) {
            for(int i = 0; i < (int) v.size(); i++) {
                if(cnt % 2 == 1) {
                    tmp.push_back(v[i]);
                }
                cnt++;
            }
        }
        else {
            for(int i = (int) v.size() - 1; i >= 0; i--){
                if(cnt % 2 == 1) {
                    tmp.push_back(v[i]);
                }
                cnt++;
            }
            reverse(tmp.begin(), tmp.end());
        }
        v = tmp;
        if(mile == 1) {
            mile = 0;
        }
        else {
            mile = 1;
        }


    }
    return v[0];

}
int main() {
    for(int i = 1; i <= 2000; i++) {
        cout << i << ": " << f(i) << endl;
    }
    return 0;
}