#include <stdio.h>

#include <stdlib.h>

#define MAX 100

int N, M;

struct Edge {

    int u,v;

    int weight;

} edge[MAX];

int vertexs[MAX];

int parents[MAX];

int edge_cmp(const void* a, const void* b) {

    return ((struct Edge*)a)->weight - ((struct Edge*)b)->weight;

}

int parents_find(int x) {

    int s;

    for(s = x; parents[s] >= 0; s = parents[s]){

        ;

    }

    return s;

}

void parents_union(int r1, int r2) {

    int s1, s2;

    int tmp;

    s1 = parents_find(r1);

    s2 = parents_find(r2);

    tmp = parents[s1] + parents[s2];

    if(parents[s1] < parents[s2]) {

        parents[s2] = s1;

        parents[s1] = tmp;

    }

    else {

        parents[s1] = s2;

        parents[s2] = tmp;

    }

}

void kruskal() {

    int sum_weight = 0;

    int num = 0;

    int i, u, v;

    for(i = 0; i < M; i++) {

        u = edge[i].u;

        v = edge[i].v;

        if(parents_find(u) != parents_find(v)) {

            printf("%d %d %d\n", u + 1, v + 1, edge[i].weight);

            num ++;

            sum_weight += edge[i].weight;

            parents_union(parents_find(u), parents_find(v));

        }

        if(num == N -1) {

            break;

        }

    }

    printf("weight of MST is %d\n", sum_weight);

}

int main() {

    int i;

    int u, v, w;

    while(1) {

        scanf("%d%d", &N, &M);

        if(N == 0 && M == 0) {

            break;

        }

        /* init */

        for(i = 0; i < N; i++) {

            vertexs[i] = i;

            parents[i] = -1;

        }

        for(i = 0; i < M; i++) {

            scanf("%d%d%d", &u, &v, &w);

            u --;

            v --;

            edge[i].u = u;

            edge[i].v = v;

            edge[i].weight = w;

        }

        /* sort */

        qsort(edge, M, sizeof(edge[0]), edge_cmp);

        kruskal();

    } 

    return 0;

}