#include <iostream>
#include <iomanip>
#include <sstream>
#include <vector>
#include <string>
#include <set>
#include <unordered_set>
#include <map>
#include <unordered_map>
#include <stack>
#include <queue>
#include <deque>
#include <algorithm>
#include <functional>
#include <iterator>
#include <limits>
#include <numeric>
#include <utility>
#include <cmath>
#include <cassert>

using namespace std; using namespace placeholders;

typedef long long LL;
typedef unsigned long long ULL;
typedef vector< int > VI;
typedef vector< VI > VVI;
typedef vector< string > VS;
typedef stringstream SS;
typedef pair< int, int > PII;
typedef vector< pair< int, int > > VPII;
#define VT( type ) vector< type >
#define VVT( type ) vector< vector< type > >
#define LIM( type ) numeric_limits< type >

template < typename T > inline istream& operator>>( istream &s, vector< T > &v ){ for ( T &t : v ) { s >> t; } return s; }
template < typename T > inline void input_n( vector< T > &out ) { copy_n( istream_iterator< T >( cin ), out.size(), out.begin() ); };
template < typename T > inline T fromString( const string &s ) { T res; istringstream iss( s ); iss >> res; return res; };
template < typename T > inline string toString( const T &a ) { ostringstream oss; oss << a; return oss.str(); };

#define REP( i, m, n ) for ( int i = (int)( m ); i < (int)( n ); ++i )
#define FOR( e, c ) for ( auto &e : c )
#define ALL( c ) (c).begin(), (c).end()
#define AALL( a, t ) (t*)a, (t*)a + sizeof( a ) / sizeof( t )
#define DRANGE( c, p ) (c).begin(), (c).begin() + p, (c).end()

#define SZ( v ) ( (int)( v ).size() )
#define PB push_back
#define EM emplace
#define EB emplace_back
#define BI back_inserter

#define EXIST( c, e ) ( ( c ).find( e ) != ( c ).end() )

#define MP make_pair
#define fst first
#define snd second

#define DUMP( x ) cerr << #x << " = " << ( x ) << endl

// Prim 法による MST
#include <vector>
#include <utility>
#include <queue>
#include <limits>
#include <type_traits>
namespace MinimumSpanningTree
{
	template < typename COST_TYPE = int, typename = typename std::enable_if< std::is_arithmetic< COST_TYPE >::value >::type >
	class Prim
	{
		typedef std::pair< COST_TYPE, int > Edge;
		const COST_TYPE INF = std::numeric_limits< COST_TYPE >::max() / 2;

		const int N;
		std::vector< std::vector< Edge > > G;

	public:
		Prim( const int n ) : N( n ), G( N )
		{
			return;
		}

		void connect( const int u, const int v, COST_TYPE c )
		{
			G[u].emplace_back( c, v );
			G[v].emplace_back( c, u );

			return;
		}

		COST_TYPE solve()
		{
			std::vector< COST_TYPE > costs( N, INF );
			costs[0] = 0;

			std::vector< bool > used( N );

			std::priority_queue< Edge, std::vector< Edge >, greater< Edge > > que;
			que.emplace( 0, 0 );

			COST_TYPE result = 0;

			while ( !que.empty() )
			{
				const COST_TYPE cost = que.top().first;
				const int u = que.top().second;
				que.pop();

				if ( used[u] )
				{
					continue;
				}

				used[u] = true;
				result += cost;

				for ( Edge &e : G[u] )
				{
					const COST_TYPE c = e.first;
					const int v = e.second;

					if ( c < costs[v] )
					{
						que.emplace( costs[v] = c, v );
					}
				}
			}

			return result;
		}
	};
}
// MinimumSpanningTree::Prim( |V| )
// connect( u, v, cost )
// solve()

int solve( const int N, const int M )
{
	MinimumSpanningTree::Prim<> prim( N );
	REP( i, 0, M )
	{
		int a, b, c;
		cin >> a >> b >> c;
		prim.connect( a, b, c );
	}

	return prim.solve();
}

int main()
{
	cin.tie( 0 );
	ios::sync_with_stdio( false );

	for ( int n, m; cin >> n >> m, ( n | m ); cout << solve( n, m ) << endl );

	return 0;
}