#include <bits/stdc++.h> using namespace std; int main() { double x, y; cin >> x >> y; vector<pair<double, double>> V = {{x, y}}; int N; cin >> N; vector<double> W(N + 1); V.resize(N + 1); for (int i = 1; i <= N; i++) cin >> V[i].first >> V[i].second >> W[i]; auto dis = [&](int a, int b) { return abs(V[a].first - V[b].first) + abs(V[a].second - V[b].second); }; vector<vector<double>> D(1 << (N + 1), vector<double>(N + 1, -1)); function<double(int, int)> F = [&](int msk, int lst) { if(D[msk][lst] >= 0) return D[msk][lst]; double w = 0; for (int i = 1; i <= N; i++) if (msk & (1 << i)) w += W[i]; double t = (w + 100) / 120; if (msk == 0) return D[msk][lst] = dis(lst, 0) * t; double ans = numeric_limits<double>::infinity(); for (int i = 1; i <= N; i++) if (msk & (1 << i)) ans = min(ans, W[i] + dis(i, lst) * t + F(msk - (1 << i), i)); return D[msk][lst] = ans; }; cout << fixed << setprecision(12) << F((1 << (N + 1)) - 2, 0) << endl; }