import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
/**
*
* @author cteam94
*/
public class FR {
private List<List<Edge>> l;
while ((new FR()).readLine(br));
}
if (line == null) {
return false;
}
String[] sp
= line.
split(" "); int root
= Integer.
parseInt(sp
[1]); l = new ArrayList<List<Edge>>();
for (int i = 0; i <= n; i++) {
l.add(new ArrayList<Edge>());
}
l.
get(root
).
add(new Edge
(root,
-1,
Integer.
MAX_VALUE));
for (int i = 0; i < n - 1; i++) {
Edge e = new Edge(v1, v2, h);
l.get(v1).add(e);
l.get(v2).add(e);
}
// System.out.println("N = " + n + ", root=" + root);
// System.out.println("List: " + l);
int x = w(root, -1);
return true;
}
public int w(int u, int p) {
List<Edge> v = l.get(u);
if (v.size() == 1) return v.get(0).h;
int c = 0;
for (int i = 0; i < v.size(); i++) {
Edge e = v.get(i);
if (e.otherEnd(u) == p) {
c2 = e.h;
} else {
c += w(e.otherEnd(u), u);
}
}
}
}
class Edge {
public int v1;
public int v2;
public int h;
public Edge(int v1, int v2, int h) {
this.v1 = v1;
this.v2 = v2;
this.h = h;
}
public int otherEnd(int v) {
if (v == v1) {
return v2;
}
if (v == v2) {
return v1;
}
return -1;
}
}