#include <bits/stdc++.h>

using namespace std;

#define MAX 100000 //maximum node

vector<int>edges[MAX];

vector<int>cost[MAX]; //parallel vector to store costs;

int main()

{

int N,E,i,j=1;

scanf("%d%d",&N,&E);

//int arr[E]={0};

int max=0;

for(i=1;i<=E;i++)

{

int x,y;

scanf("%d%d",&x,&y);

if(x==y){

edges[x].push_back(y);

//edges[y].push_back(x);

cost[x].push_back(1);

cost[y].push_back(1);

}

else{

edges[x].push_back(y);

edges[y].push_back(x);

cost[x].push_back(1);

cost[y].push_back(1);}

// arr[j]=edges[x][0];

j++;

}

for(int i=1;i<=N;i++)

{

int size=edges[i].size();

printf("%d->",i);

for(int k=0; k <size; ++k)

{

printf("%d ",edges[i][k]);

}

printf("\n");

}

return 0;

}

/*

6 8

1 2

1 4

2 4

2 5

4 5

5 3

3 6

6 6

*/