#include <cmath>#include <vector>#include <cstdio>using namespace std;int pre[512], tag[512], dis[512], cc;vector<int> e[512];void dfs(int n, int p, int c, int d){ for (size_t i = 0; i < e[p].size(); i++) { if (pre[e[p][i]] == -1) { pre[e[p][i]] = p; tag[e[p][i]] = c; dis[e[p][i]] = d + 1; ++cc; dfs(n, e[p][i], c, d + 1); } }}int cnt[512];int handle(int n){ int ret = 0, t, tt; for (int i = 0; i < n; i++) { pre[i] = -1; e[i].clear(); } for (int i = 1; i < n; i++) { scanf("%d", &t); e[i - 1].push_back(t); e[t].push_back(i - 1); } pre[0] = -2; dis[0] = 0; dfs(n, 0, 0, 0); t = n - 1; do { tt = pre[t]; pre[t] = -2; tag[t] = dis[t]; dis[t] = 0; t = tt; } while (t != -2); for (int i = 0; i < n; i++) { if (pre[i] != -2) { pre[i] = -1; } } for (int i = 0; i < n; i++) { if (pre[i] == -2) { ++ret; cc = 1; dfs(n, i, tag[i], 0); cnt[tag[i]] = cc; } } return ret;}double calc_x(int m, double x, double y){ double ret = 0; for (int i = 1; i <= m; i++) { ret += x / hypot(x, y); y += cnt[i]; } return ret;}double calc_y(int m, double x, double y){ double ret = 0; for (int i = 1; i <= m; i++) { ret += y / hypot(x, y); y += cnt[i]; } return ret;}int main(void){ int n, m, k; double s, lx, rx, mx, ly, ry, my, xx, yy; while (scanf("%d%lf%d", &n, &s, &k) != EOF) { m = handle(n) - 1; lx = 0; rx = 1e11; while (rx - lx > 1e-8) { mx = (lx + rx) / 2; ly = -n; ry = n; while (ry - ly > 1e-8) { my = (ly + ry) / 2; yy = calc_y(m, mx, my); if (yy >= 0) { ry = my; } else { ly = my; } } my = (ly + ry) / 2; xx = calc_x(m, mx, my); if (xx >= s) { rx = mx; } else { lx = mx; } } mx = (lx + rx) / 2; xx = 0; yy = 0; for (int i = 1; i <= tag[k]; i++) { xx += mx / hypot(mx, my); yy += my / hypot(mx, my); my += cnt[i]; } yy -= dis[k]; printf("%.3lf %.3lfn", xx, yy); } return 0;}
