int n, m, x[15], y[15], p, q;
double w[15], dp[1 << 15][15], ww[1 << 15];
double calc(int i, int j, double weight) {
	return (weight + 100.0) / 120.0 * (abs(x[i] - x[j]) + abs(y[i] - y[j]));
}
{
	rd(p, q, n, (x, y, w)(n));
	x[n] = p;
	y[n] = q;
	m = 1 << n;
	double sum_w = sum(w(n));
	rep(i, m) rep(j, n) dp[i][j] = ll_inf;
	rep(v, n) dp[m - 1][v] = calc(v, n, 0);
	ww[m - 1] = sum_w;
	rrep(s, m - 1) {
		rep(v, n) rep(u, n) {
			if (!(s & 1 << u)) {
				ww[s] = ww[s | 1 << u] - w[u];
				dp[s][v] <?= dp[s | 1 << u][u] + calc(v, u, ww[s]);
			}
		}
	}
	double ans = ll_inf;
	rep(i, n) ans <?= dp[0][i] + calc(i, n, sum_w);
	wt(ans + sum_w);
}