#include <map>

#include <ctime>

#include <cmath>

#include <queue>

#include <cstdio>

#include <cstring>

#include <iostream>

#include <algorithm>

using namespace std;

#define F(i,j,k) for (int i=j;i<=k;++i)

#define D(i,j,k) for (int i=j;i>=k;--i)

#define maxn 20005

int h[maxn],to[maxn],ne[maxn],du[maxn],w[maxn],en=0,n,m;

double a[105][105],ans[105];

void add(int a,int b,int c)

{du[a]++;to[en]=b;ne[en]=h[a];w[en]=c;h[a]=en++;}

void Gauss()

{

    F(i,1,n-1)

    {

        int tmp=i;

        F(j,i,n-1)if(fabs(a[j][i])>fabs(a[tmp][i]))tmp=j;

        F(j,i,n+1) swap(a[i][j],a[tmp][j]);

        F(j,i+1,n-1)

        {

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

            F(k,i,n+1) a[j][k]-=a[i][k]*tmp;

        }

    }

    D(i,n-1,1)

    {

        F(j,i+1,n)

            a[i][n+1]-=a[i][j]*ans[j];

        ans[i]=a[i][n+1]/a[i][i];

    }

}

double ret=0.0;

void solve(int x)

{

    memset(a,0,sizeof a);

    memset(ans,0,sizeof ans);

    F(i,1,n-1)

    {

        for (int j=h[i];j>=0;j=ne[j])

            if ((w[j]>>x)&1)

                a[i][to[j]]+=1,a[i][n+1]+=1;

            else a[i][to[j]]-=1;

        a[i][i]+=du[i];

    }

//  F(i,1,n) F(j,1,n+1) printf("%.6f%c",a[i][j],j==n+1?'\n':' ');printf("\n\n");

    Gauss();

    ret+=ans[1]*(1<<x);

}

int main()

{

    memset(h,-1,sizeof h);

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

    F(i,1,m)

    {

        int a,b,c;

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

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

    }

    D(i,30,0) solve(i);

    printf("%.3f\n",ret);

}