#include <vector>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <algorithm>
#include <utility>
#include <functional>
#include <sstream>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <climits>
#include <fstream>
using namespace std;
inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v;}
template<class T> inline string toStr(T x) { ostringstream sout; sout << x; return sout.str();}
typedef vector<int> vi;
typedef vector<vi>  vvi;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef long long ll;
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define REP(i,n) FOR(i,0,(n)-1)
const double EPS = 1e-12;
const double PI = acos(-1.0);
const int INF = INT_MAX/10;

struct state {
	int p, c;
	state(int p, int c) : p(p), c(c) {};
	bool operator<(const state &o)const {
		return o.c<c;
	}
};

int main() {
	int n, m;
	while(cin >> n >> m, n) {
		int a, b, c;
		vvi dist(n, vi(n, INF));
		REP(i, m) {
			cin >> a >> b >> c;
			dist[a][b] = min(dist[a][b], c);
			dist[b][a] = min(dist[b][a], c); 
		}

		priority_queue<state> Q;
		vi used(n);
		Q.push(state(0, 0));
		int ans = 0;
		while(!Q.empty()) {
			state st = Q.top();
			Q.pop();

			if(used[st.p]) {
				continue;
			}

			used[st.p] = 1;
			ans += st.c;

			REP(i, n) {
				if(dist[st.p][i] != INF && st.p != i) {
					Q.push(state(i, dist[st.p][i]));
				}
			}
		}

		cout << ans << endl;
	}

	return 0;
}