bfs

#include<bits/stdc++.h>
using namespace std;;

vector<int> v[100];
vector<int>vis(100);


int main(){
    int n,m,a,b;cin>>n>>m;
    while(m--){
        cin>>a>>b;
        v[a].push_back(b);v[b].push_back(a);
    }
    queue<int> q;
    q.push(1);vis[1]=true;
    while(!q.empty()){
        int src=q.front();q.pop();
        cout<<src<<" ";
        for(int i=0;i<v[src].size();i++){
            if(vis[v[src][i]]==false){
               q.push(v[src][i]);
               vis[v[src][i]]=true;
            }
        }
    }

}