16

#include <iostream>

using namespace std;

int g[4][4] = {
    {0, 1, 1, 0},
    {1, 0, 0, 0},
    {1, 0, 0, 1},
    {0, 0, 1, 0},
};
int used[4];

void DFS(int v) {
    cout << v + 1 << " ";
    used[v] = true;
    for (int j = 0; j < 4; ++ j) {
        if (g[v][j] != 0 && !used[j]) DFS(j);
    }
}

int main() {
    for (int i = 0; i < 4; ++ i)
        if (!used[i]) {
            DFS(i);
            cout << endl;
        }
    return 0;
}