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