#include <bits/stdc++.h>
using namespace std;
#ifdef DEBUG
#define dbg(...) printf(__VA_ARGS__);
#define getchar_unlocked getchar
#else
#define dbg(...)
#endif
#define sf scanf
#define pf printf
#define fi first
#define se second
#define pb push_back
#define sz(x) (int)x.size()
#define mnto(x,y) x=min(x,(__typeof__(x))y)
#define mxto(x,y) x=max(x,(__typeof__(x))y)
#define INF 1023456789
#define LINF 1023456789123456789
#define all(x) x.begin(), x.end()
#define disc(x) sort(all(x));x.resize(unique(all(x))-x.begin());
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<ll, ll> pll;
typedef tuple<int, int, int> iii;
typedef tuple<int, int, int, int> iiii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<pll> vll;
mt19937 rng(time(0));
#define mod 1000000007
inline int add(int a,int b){
int r=a+b;
while(r>=mod)r-=mod;
while(r<0)r+=mod;
return r;
}
inline int mult(int a,int b){
return (int)(((ll)(a*b))%mod);
}
inline int rd(){
int x=0;
char ch=getchar_unlocked();
while(ch<'0'||ch>'9')ch=getchar_unlocked();
while(ch>='0'&&ch<='9'){
x=(x<<3)+(x<<1)+ch-'0';
ch=getchar_unlocked();
}
return x;
}
#define maxn 200005
int n,a,b,ans;
vi AL[maxn];
char s[maxn];
int dfs(int u,int p){
int v0=0,v1=0,sm=0,mx=0;
for(int v:AL[u]){
if(v==p)continue;
int tmp=dfs(v,u);
sm+=max(tmp,0);
mx=max(mx,tmp);
}
int t=(s[u-1]-'0');
v0=max(sm-t,mx+t);//first one
v1=max(sm-t,t);//>1 on top
ans=max(ans,max(v0,v1));
return v1;
}
int main(){
sf("%d",&n);
for(int i=1;i<n;++i){
sf("%d%d",&a,&b);
AL[a].pb(b);
AL[b].pb(a);
}
sf(" %s",&s);
dfs(1,1);
pf("%d\n",ans);
}
