#include <iostream>
#include <cstdio>

//struct Edge {
//  int first;
//  int second;
//};

void dfs(size_t** graph, size_t vertex, size_t* colors, size_t color, size_t vertices_count);

int main() {
  FILE* file = fopen("input", "r");
  size_t N;
  fscanf(file, "%lu", &N);
  size_t** graph = (size_t**)calloc(N + 1, sizeof(size_t*));

  for (size_t i = 0; i < N + 1; ++i) {
    graph[i] = (size_t*)calloc(N + 1, sizeof(size_t));
  }

  size_t left, right;
  while(fscanf(file, "%lu %lu", &left, &right) != EOF) {
    graph[left][right] = 1;
    graph[right][left] = 1;
  }

  size_t* colors = (size_t*)calloc(N + 1, sizeof(size_t));

  size_t color = 1;
  for (size_t i = 0; i < N + 1; ++i) {
    if (colors[i] == 0) {
      colors[i] = color;
      dfs(graph, i, colors, color, N + 1);
      ++color;
    }
  }

  for (size_t i = 1; i < color; ++i) {
    for (size_t j = 0; j < N + 1; ++j) {
      if (colors[j] == i) {
        std::cout << j << ' ';
        fflush(stdin);
      }
    }
    std::cout << std::endl;
  }

  return 0;
}

void dfs(size_t** graph, size_t vertex, size_t* colors, size_t color, size_t vertices_count) {
  for (size_t i = 0; i < vertices_count; ++i) {
    if (graph[vertex][i]) {
      if (colors[i] == 0) {
        colors[i] = color;
        dfs(graph, i, colors, color, vertices_count);
      }
    }
  }
}