1 #include <cmath>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <iostream>
 5 #include <algorithm>
 6 using namespace std;
 7 int father[200200];
 8 int n, m;
 9 struct rode
10 {
11     int x, y, w;
12 } num[200200], shu[200200];
13 
14 bool cmp(rode x, rode y)
15 {
16     return x.w > y.w;
17 }
18 
19 bool cpm(rode x, rode y)
20 {
21     return x.w < y.w;
22 }
23 
24 void init()
25 {
26     for(int i = 0; i < n; i++)
27         father[i] = i; 
28 }
29 
30 int find(int a)
31 {
32     if(a == father[a])
33         return a;
34     else
35         return father[a] = find(father[a]);
36 }
37 
38 bool mercy(int a, int b)
39 {
40     int q = find(a);
41     int p = find(b);
42     if(q != p)
43     {
44         father[q] = p;
45         return true;
46     }
47     else
48         return false;
49 }
50 
51 int main()
52 {
53     while(~scanf("%d %d", &n, &m), n+m)
54     {
55         init(); int sum = 0;
56         for(int i = 0; i < m; i++)
57         {
58             scanf("%d %d %d", &num[i].x, &num[i].y, &num[i].w);
59             shu[i].x = num[i].x; shu[i].y = num[i].y; shu[i].w = num[i].w;
60             sum += num[i].w;
61         }
62         /*int sum = 0;
63         sort(num, num + m, cmp);
64         for(int i = 0; i < m; i++)
65         {
66             if(mercy(num[i].x, num[i].y))
67                 sum += num[i].w;
68         }*/
69         int total = 0;
70         sort(shu, shu + m, cpm);
71         for(int i = 0; i < m; i++)
72         {
73             if(mercy(shu[i].x, shu[i].y))
74                 total += shu[i].w;
75         } 
76         printf("%d\n", abs(sum - total));
77     }
78     return 0;
79 }