#include<cstdio>
using namespace std;
const int pinf=100001;
int main()
{
    freopen("ubuntzei.in","r",stdin);
    freopen("ubuntzei.out","w",stdout);

    int n,a[201][201],v[63365],i,j,k,m,x,y,c;
    scanf("%d %d",&n, &m);
    scanf("%d",&k);
    for(i=1;i<=k;i++)
      scanf("%d",&v[i]);
    for(i=1;i<=n;i++)
      for(j=1;j<=n;j++)
        if(i==j) a[i][j]=0; else a[i][j]=pinf;
    for(i=1;i<=m;i++)
       {
         scanf("%d %d %d", &x,&y,&c) ;
          a[x][y]=a[y][x]=c;
       }

     for(k=1;k<=n;k++)
        for(i=1;i<=n;i++)
          for(j=1;j<=n;j++)
            if(a[i][j]>a[i][k]+a[k][j])
               a[i][j]=a[i][k]+a[k][j];
    printf("%d\n", a[1][n]);
       return 0;
}