#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define pb push_back
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
const int mxN = 200'005;
vector<int> adj[mxN];
ll dp[mxN][2][2];
bool power[mxN];
// dp[n][on/off][there is/isn't a turned on child outside of his subtree]
void dfs(int s, int e) {
ll mx1=0;
ll mx2=0;
ll sum=0;
for (int u: adj[s]){
if (u == e) continue;
dfs(u, s);
sum += max(dp[u][0][1], dp[u][1][1]);
mx1 = max(dp[u][0][0], dp[u][1][0]);
mx2 = max(dp[u][0][1], dp[u][1][1]);
}
dp[s][0][0] = max(sum-power[s], mx1);
dp[s][0][1] = sum-power[s];
dp[s][1][0] = mx2+power[s];
dp[s][1][1] = power[s];
}
int main(){
ios::sync_with_stdio(false);
cin.tie(0);
int n; cin >> n;
for (int i = 0; i < n-1; i++) {
int u, v; cin >> u >> v;
adj[u].pb(v), adj[v].pb(u);
}
string s; cin>>s;
for (int i=0;i<n;i++) power[i+1]=s[i]=='1';
dfs(1, 0);
cout << max(
{dp[1][0][0], dp[1][0][1], dp[1][1][0], dp[1][1][1]}
)
<< endl;
}
