#include <cstdio>
#include <cstring>
#include <queue>
#define inf 0x3f3f3f3f
using namespace std;
queue<int> q;
int map[160][160] , head[400] , to[100000] , val[100000] , cost[100000] , next[100000] , cnt = 1 , s , t , dis[400] , from[400] , pre[400];
void add(int x , int y , int v , int c)
{to[++cnt] = y , val[cnt] = v , cost[cnt] = c , next[cnt] = head[x] , head[x] = cnt;to[++cnt] = x , val[cnt] = 0 , cost[cnt] = -c , next[cnt] = head[y] , head[y] = cnt;
}
bool spfa()
{int x , i;memset(dis , 0x3f , sizeof(dis));memset(from , -1 , sizeof(from));dis[s] = 0 , q.push(s);while(!q.empty()){x = q.front() , q.pop();for(i = head[x] ; i ; i = next[i])if(val[i] && dis[to[i]] > dis[x] + cost[i])dis[to[i]] = dis[x] + cost[i] , from[to[i]] = x , pre[to[i]] = i , q.push(to[i]);}return ~from[t];
}
int mincost()
{int ans = 0 , i , k;while(spfa()){k = inf;for(i = t ; i != s ; i = from[i]) k = min(k , val[pre[i]]);ans += dis[t] * k;for(i = t ; i != s ; i = from[i]) val[pre[i]] -= k , val[pre[i] ^ 1] += k;}return ans;
}
int main()
{int n , m , p , i , j , k , x , y , z;scanf("%d%d%d" , &n , &m , &p);memset(map , 0x3f , sizeof(map));while(m -- ) scanf("%d%d%d" , &x , &y , &z) , map[x][y] = map[y][x] = min(map[x][y] , z);for(k = 0 ; k <= n ; k ++ )for(i = 0 ; i <= n ; i ++ )for(j = 0 ; j <= n ; j ++ )if((k <= i || k <= j) && map[i][j] > map[i][k] + map[k][j])map[i][j] = map[i][k] + map[k][j];s = 2 * n + 2 , t = 2 * n + 3 , add(2 * n + 1 , 0 , p , 0);for(i = 1 ; i <= n ; i ++ ) add(0 , i , inf , map[0][i]);for(i = 1 ; i <= n ; i ++ ){add(s , i + n , 1 , 0) , add(i , t , 1 , 0) , add(i + n , 2 * n + 1 , inf , 0);for(j = i + 1 ; j <= n ; j ++ )if(map[i][j] != inf)add(i + n , j , inf , map[i][j]);}printf("%d\n" , mincost());return 0;
}