#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> ii;
typedef vector<ll> vi;
typedef vector<vi> vvi;
typedef vector<vvi> vvvi;
typedef vector<vvvi> vvvvi;
typedef vector<ii> vii;

#define x first
#define y second
#define pb push_back
#define eb emplace_back
#define all(v) (v).begin(), (v).end()

unordered_map<string, ll> M;
ll m = 0;
vector<vector<pair<ll, ld>>> adj;

ll get_index(string s) {
	if (M.find(s) == M.end()) {
		M[s] = m;
		m++;
		adj.pb(vector<pair<ll, ld>>());
	}
	return M[s];
}

ld dfs(ll i, ll p, ll j, ld a) {
	if (i == j) return a;
	for (pair<ll, ld> t : adj[i]) {
		if (t.x == p) continue;
		ld r = dfs(t.x, i, j, a*t.y);
		if (r > 0) return r;
	}
	return -1;
}

void run() {
	ll n, q;
	cin >> n >> q;
	for (ll i = 0; i < n; i++) {
		ld a, b;
		string c, d, e;
		cin >> a >> c >> d >> b >> e;
		ll u1 = get_index(c), u2 = get_index(e);
		adj[u1].pb({u2, b});
		adj[u2].pb({u1, 1/b});
	}
	for (ll i = 0; i < q; i++) {
		ld a;
		string b, c, d;
		cin >> a >> b >> c >> d;
		ld r = dfs(get_index(b), -1, get_index(d), a);
		if (r > 0) cout << r << endl;
		else cout << "impossible" << endl;
	}

}

signed main() {
    ios_base::sync_with_stdio(false); cin.tie(0);
	cout << fixed << setprecision(20); // With "fixed", small numbers are printed as "0.0000000..."
    run();
    return 0;
}