#define Linux_System
	
#include <bits/stdc++.h>
	
# ifdef Linux_System
# define getchar getchar_unlocked
# define putchar putchar_unlocked
# endif
	
using namespace std;
	
const int maxn = 10000009;
	
template <class T>
inline bool scan_d(T & ret)
{
	char c;
	int sgn;
	if(c = getchar(), c == EOF)return false;
	while(c != '-' && (c < '0' || c > '9'))c = getchar();
	sgn = (c == '-') ? -1 : 1;
	ret = (c == '-') ? 0 : (c - '0');
	while(c = getchar(), c >= '0' && c <= '9')
		ret = ret * 10 + (c - '0');
	ret *= sgn;
	return true;
}
	
template <class T>
inline void out_number(T x)
{
	if(x < 0)
	{
		putchar('-');
		out_number(- x);
		return ;
	}
	if(x > 9)out_number(x / 10);
	putchar(x % 10 + '0');
}
	
int n, m;
int A[maxn], fa[maxn], sum[maxn];
	
ll dfs(int i)
{
	if(! fa[i])
	{
		sum[i] -= A[i]; //clear the initial point
		return abs(sum[i]);
	}
	ll x = 0;
	A[i] += sum[fa[i]]; //clear the tag of this point
	x += abs(A[i]);
	sum[i] += sum[fa[i]] - A[i]; //clear the tag of now
	return x;
}
	
int main()
{
	ll ans = 0;
//	scanf("%d", &n);
	scan_d(n);
	fa[1] = 0;
	for(register int i = 1, u, v; i < n; ++ i)
	{
		//scanf("%d %d", &u, &v);
		scan_d(u);
		scan_d(v);
		fa[v] = u;
	}
	for(register int i = 1; i <= n; ++ i) scan_d(A[i]); //scanf("%d", A + i);
	for(register int i = 1; i <= n; ++ i) ans += dfs(i);
	printf("%lld\n", ans);
	return 0;
}