#include<iostream>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<queue>
#include<iomanip>
using namespace std;
const int N = 2010,M=2e5+10;
typedef pair<double,int> PDI;
int h[N],ne[M],e[M],idx;
double w[M];
int n,m;
int A,B;
bool st[N];
double dist[N];

void add(int a,int b,double c)
{
    e[idx] = b;
    ne[idx] = h[a];
    w[idx] = c;
    h[a] = idx++;
}

double dijkstra()
{
    for(int i=0;i<=n;i++) dist[i] = 100;
    dist[A] = 0;
    priority_queue<PDI,vector<PDI>,greater<PDI>> heap;
    heap.push({0,A});

    while(heap.size())
    {
        auto t = heap.top();
        heap.pop();

        double d = t.first; int ver = t.second;

        if(!st[ver]) st[ver] = true;
        else continue;

        for(int i=h[ver];~i;i=ne[i])
        {
            int j = e[i];
            if(dist[j] > d + w[i])
            {
                dist[j] = d+w[i];
                heap.push({dist[j],j});
            }
        }
    }
    return dist[B];
}

int main()
{

    memset(h,-1,sizeof h);


    cin>>n>>m;
    while(m--)
    {
        int a,b,c; cin>>a>>b>>c;
        double t = (100.0-c)/100;
        add(a,b,-log(t));
        add(b,a,-log(t));
    }

    cin>>A>>B;

    dijkstra();

    cout <<fixed<<setprecision(8);
    cout<<100.0/exp(-dist[B]);
    return 0;
}