# include <bits/stdc++.h> using namespace std ; double a [1005] [1005] , dis [1005] , f [1005] , maxn ; int k ; int main ( ) { int n , m ; cin >> n >> m ; while ( m -- ) { int x , y , z ; cin >> x >> y >> z ; a [x] [y] = a [y] [x] = 0.01 * ( 100 - z ) ; } int x , y ; cin >> x >> y ; for ( int i = 1 ; i <= n ; i ++ ) { dis [i] = a [x] [i] ; } dis [x] = 1 ; f [x] = 1 ; for ( int i = 1 ; i < n ; i ++ ) { maxn = 0 ; for ( int j = 1 ; j <= n ; j ++ ) { if ( f [j] == 0 && dis [j] > maxn ) { k = j ; maxn = dis [j] ; } } f [k] = 1 ; if ( ! ( k - y ) ) { break ; } for ( int j = 1 ; j <= n ; j ++ ) { if ( f [j] == 0 && dis [k] * a [k] [j] > dis [j] ) { dis [j] = dis [k] * a [k] [j] ; } } } cout << fixed << setprecision ( 8 ) << 100 / dis [y] << endl ; return 0 ; }