#include<cstdio>
#include<cstring>
#include<string>
#include<cmath>
#include<vector>
#include<queue>
#include<algorithm>
using namespace std;const int maxn=1000+10;
const int INF=0x7FFFFFFF;struct Edge
{int from,to,cap,flow;
};
vector<Edge>edges;
vector<int>G[maxn];
vector<int>CG[maxn];
bool vis[maxn];
int d[maxn];
int cur[maxn];
int n,m,s,t;
Edge P[maxn];//求出层次网络
bool BFS()
{memset(vis,0,sizeof(vis));queue<int>Q;Q.push(s);d[s]=0;vis[s]=1;while(!Q.empty()){int x=Q.front();Q.pop();for(int i=0; i<G[x].size(); i++){Edge& e=edges[G[x][i]];if(!vis[e.to]&&e.cap>e.flow){vis[e.to]=1;d[e.to]=d[x]+1;Q.push(e.to);}}}return vis[t];
}//加边
void AddEdge(int from,int to,int cap)
{Edge r;r.from=from;r.to=to;r.cap=cap;r.flow=0;edges.push_back(r);Edge d;d.from=to;d.to=from;d.cap=0;d.flow=0;edges.push_back(d);m=edges.size();G[from].push_back(m-2);G[to].push_back(m-1);
}//每个阶段来一次DFS增广
int DFS(int x,int a)
{if(x==t||a==0) return a;int flow=0,f;for(int i=cur[x]; i<G[x].size(); i++){Edge& e=edges[G[x][i]];if(d[x]+1==d[e.to]&&(f=DFS(e.to,min(a,e.cap-e.flow)))>0){e.flow+=f;edges[G[x][i]^1].flow-=f;flow+=f;a-=f;if(a==0) break;}}return flow;
}//多个阶段，多次建立层次网络。
int Maxflow(int ss,int tt)
{int flow=0;while(BFS()){memset(cur,0,sizeof(cur));flow+=DFS(ss,INF);}return flow;
}int N,M,Cost;
int U[maxn],V[maxn];
int FF[maxn];void dfs(int x)
{FF[x]=1;for(int i=0; i<CG[x].size(); i++)if(!FF[CG[x][i]])dfs(CG[x][i]);
}int main()
{while(~scanf("%d%d",&N,&M)){if(!N&&!M) break;edges.clear();for(int i=0; i<maxn; i++) G[i].clear();for(int i=0; i<maxn; i++) CG[i].clear();memset(FF,0,sizeof FF);s=1;t=2;for(int i=1; i<=M; i++){scanf("%d%d%d",&U[i],&V[i],&Cost);AddEdge(U[i],V[i],Cost);AddEdge(V[i],U[i],Cost);}Maxflow(s,t);int Tot=0;for(int i=0; i<edges.size(); i=i+2){P[Tot].from=edges[i].from;P[Tot].to=edges[i].to;P[Tot].cap=edges[i].cap;P[Tot].flow=edges[i].flow;Tot++;}for(int i=0; i<Tot; i++){if(P[i].cap-P[i].flow>0)CG[P[i].from].push_back(P[i].to);if(P[i].flow>0)CG[P[i].to].push_back(P[i].from);}dfs(s);for(int i=1; i<=M; i++)if((FF[U[i]]==0&&FF[V[i]]==1)||(FF[V[i]]==0&&FF[U[i]]==1))printf("%d %d\n",U[i],V[i]);printf("\n");}return 0;
}