#include <set>#include <map>#include <list>#include <cmath>#include <ctime>#include <deque>#include <queue>#include <stack>#include <cstdio>#include <string>#include <vector>#include <cctype>#include <cstring>#include <sstream>#include <fstream>#include <cstdlib>#include <cassert>#include <iostream>#include <algorithm>

using namespace std;//Constant Declaration/*--------------------------*///#define LL long long #define LL __int64const int M=250;//最多点数const int INF=1<<30;const double EPS = 1e-11;const double PI = acos(-1.0);/*--------------------------*/// some essential funtion/*----------------------------------*/void Swap(int &a,int &b){   int t=a;a=b;b=t; }int Max(int a,int b){   return a>b?a:b;  }int Min(int a,int b){   return a<b?a:b;  }int Gcd(int a,int b){   while(b){b ^= a ^=b ^= a %= b;}  return a; }/*----------------------------------*///for (i = 0; i < n; i++)/*----------------------------------*/

int d[M];//表示i到源点的最短距离int g[M][M];//邻接矩阵bool used[M];//标记i是否被用过

void init(int n){int i, j;for (i = 0; i < n; i++)    {for (j = 0; j < n; j++)        {            g[i][j] = INF;//初始化图没有边，默认为INF,为了一定更新        }    }for (i = 0; i < n; i++)    {        d[i] = INF;    }

    memset(used, false, sizeof(used));}

int dijkstra(int star, int end, int n)//起点，终点，总点数(编号为1,2...n){int min_num = 1;//最小值的位置    int i;    d[star] = 0;//起点到起点的最短距离为0，很重要的一步    for (int cnt = 0; cnt < n; cnt++)//注意别用while(n--),这样会改变n的值。n次贪心    {int min = INF;for (i = 0; i < n; i++)        {if (!used[i] && d[i] < min)            {                min = d[i];                min_num = i;            }        }

        used[min_num] = 1;

//把d[min_num]作为中间点，对相邻的点做松弛        for (i = 0; i < n; i++)        {if (!used[i] && d[i] > d[min_num] + g[min_num][i])            {                d[i] = d[min_num] + g[min_num][i];            }        }

    }return d[end];}int main(){//freopen("in.txt","r",stdin);//freopen("out.txt","w",stdout);//int t, case1 = 0;//scanf("%d", &t); int n, m;int i, j;while (scanf("%d%d", &n, &m) != EOF) {     init(n);while (m--)    {int a, b, c;        scanf("%d%d%d", &a, &b, &c);        g[b][a] = g[a][b] = Min(c, g[a][b]);//此题为无向图    }int star, end;    scanf("%d%d", &star, &end);int ans = dijkstra(star, end, n);if(INF == ans)    {        puts("-1");    }else    {      printf("%d\n", ans);    } }

return 0;}