#include<cmath>

 #include<cstdio>

 #include<cstring>

 #include<algorithm>

 struct pnt{

     int hd;

     int ind;

 }p[];

 struct ent{

     int twd;

     int lst;

     int vls;

 }e[];

 double a[][];

 int cnt;

 int n,m;

 void ade(int f,int t,int v)

 {

     cnt++;

     e[cnt].vls=v;

     e[cnt].twd=t;

     e[cnt].lst=p[f].hd;

     p[f].hd=cnt;

     p[f].ind++;

     return ;

 }

 void G_(void)

 {

     for(int i=;i<=n;i++)

     {

         int h=i;

         for(int j=i+;j<=n;j++)if(fabs(a[h][i])<fabs(a[j][i]))h=j;

         if(h!=i)for(int j=i;j<=n+;j++)std::swap(a[i][j],a[h][j]);

         for(int j=i+;j<=n;j++)

         {

             double s=a[j][i]/a[i][i];

             for(int k=i;k<=n+;k++)a[j][k]-=a[i][k]*s;

         }

     }

     for(int i=n;i>;i--)

     {

         for(int j=i-;j>;j--)

         {

             a[j][n+]-=a[i][n+]/a[i][i]*a[j][i];

         }

     }

     return ;

 }

 int main()

 {

 //    freopen("a.in","r",stdin);

     scanf("%d%d",&n,&m);

     for(int i=;i<=m;i++)

     {

         int a,b,c;

         scanf("%d%d%d",&a,&b,&c);

         ade(a,b,c);if(a!=b)ade(b,a,c);

     }

     double ans=;

     for(int i_=;(1ll<<i_)<=(long long)(1e9);i_++)

     {

         memset(a,,sizeof(a));

         for(int i=;i<=n;i++)

         {

             a[i][i]=p[i].ind;if(i==n)continue;

             for(int i__=p[i].hd;i__;i__=e[i__].lst)

             {

                 int j=e[i__].twd;

                 if(e[i__].vls&(<<i_))a[i][j]+=1.00,a[i][n+]+=1.00;

                 else                  a[i][j]-=1.00;

             }

         }

         G_();double ps=a[][n+]/a[][];

         ans+=ps*(1ll<<i_);

     }

     printf("%.3lf\n",ans);

     return ;

 }