#include <bits/stdc++.h>
 
using namespace std;
 
#define READ(f) freopen(f, "r", stdin)
#define WRITE(f) freopen(f, "w", stdout)
 
#define rep(i,n) for(int i = 0 ; i < (n) ; i++)
#define iter(i,a,b) for(int i = (a) ; i < (b) ; i++)
#define mem(a,b) memset(a,b,sizeof(a))
 
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<int,pii> iii;
typedef vector <pii> vii;
 
#define INF 1000000000
#define MAXX 200005
 
vii adj_l[MAXX];
vector<bool> taken;
priority_queue<pii> pq;
int V, E;
 
void init(){
	rep(i, MAXX){
		adj_l[i].clear();
	}
	taken.clear();
	while(!pq.empty())
		pq.pop();
}
 
void input(int u, int v, int w){
	adj_l[u].push_back(make_pair(v, w));
	adj_l[v].push_back(make_pair(u, w));
}
 
void process(int src){
	taken[src] = true;
	rep(i, (int)adj_l[src].size()){
		pii v = adj_l[src][i];
		if(!taken[v.first])
			pq.push(pii(-v.second, -v.first));
	}
}
 
int primMST(int src){
	process(src);
	int mst_cost = 0;
	while(!pq.empty()){
		pii nxt = pq.top();
		pq.pop();
		int u = -nxt.second;
		int w = -nxt.first;
		if(!taken[u]){
			mst_cost += w;
			process(u);
		}
	}
	printf("%d\n", mst_cost);
}
 
int main(){
	READ("UVa 11631.txt");
	int u, v, w;
	while(1){
		cin>>V>>E;
		if(V == 0 && E == 0)
			break;
		init();
		rep(i, E){
			cin>>u>>v>>w;
			input(u, v, w);
		}
		primMST(0);
	}
	return 0;
}
 
 

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7 11
0 1 7
0 3 5
1 2 8
1 3 9
1 4 7
2 4 5
3 4 15
3 5 6
4 5 8
4 6 9
5 6 11
0 0