#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;
 
//Kruskal最小生成树模板题
int n, m, father[100000];
 
struct node{
    int src, dst;
    int val;
};
 
bool cmp(node a, node b){return a.val < b.val;}
 
int findFather(int a){
    int t = a;
    while(a != father[a])a = father[a]; //找到根节点
    return a;
}
 
void init(){
    for(int i = 1; i <= n; i++)father[i] = i;
}
 
int unionSet(int x, int y){ //和并查集一样，如果将根合并
    int fx = findFather(x);
    int fy = findFather(y);
    if(fx != fy){
        father[fx] = fy;
        return  1;
    }return 0;
}
 
int main(){
    while(cin>>n){
        if(n == 0)break;
        init(); //初始化不能丢
        cin>>m;
        int ans = 0;
        vector<node> pool(m);
        for(int i = 0; i < m; i++){
            cin>>pool[i].src>>pool[i].dst>>pool[i].val;
        }
        
        sort(pool.begin(), pool.end(), cmp);
        int k = 0, i = 0;
        while(k < n - 1){ 
            if(unionSet(pool[i].src, pool[i].dst)){ //如果两个节点的根不一样则合并，本质上将两个预给定的边选择出来
                //也不会成环
                k++;
                ans += pool[i].val;
            }
            i++;
        }
        cout<<ans<<endl;
    }
    return 0;
}