#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;

const int N = 100010 , M = 2 * N;
int h[N], e[M], ne[M], idx;

void add(int a, int b)  // 添加一条边a->b
{
    e[idx] = b, ne[idx] = h[a], h[a] = idx ++ ;
}

int main()
{
    memset(h, -1, sizeof h);

    add(1,2);
    add(2,1);

    for(int i = h[1];~i;i=ne[i])
    {
        int j = e[i];
        int fa = e[i^1];
        cout << fa << endl;
    }
}