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

vector<int> graph[10];
bool visited[10];

void dfs(int x) {
    visited[x] = true;
    cout << x << " ";

    for(int i = 0; i < graph[x].size(); i++) {
        int next = graph[x][i];
        if(visited[next] == false) {
            dfs(next);
        }
    }
}

int main() {
    graph[1].push_back(2);
    graph[1].push_back(3);
    graph[2].push_back(4);
    graph[2].push_back(5);

    dfs(1);
}