#include <bits/stdc++.h>
using namespace std;
typedef signed long long ll;

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
//-------------------------------------------------------

int N;
vector<int> R[201010],B[201010];
int ret;
int ma;

int dfs(int cur,int pre,int d) {
	vector<int> C;
	if(B[cur].size()%2) C.push_back(d);
	FORR(e,R[cur]) if(e!=pre) {
		int v=dfs(e,cur,d+1);
		if(v!=-1) C.push_back(v);
	}
	
	sort(ALL(C));
	while(C.size()>1) {
		int add=C.back()+C[C.size()-2]-2*d;
		ma=max(ma,add);
		ret+=add;
		C.pop_back();
		C.pop_back();
	}
	if(C.empty()) return -1;
	else return C[0];
}


void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>N;
	FOR(i,N-1) {
		cin>>x>>y;
		R[x-1].push_back(y-1);
		R[y-1].push_back(x-1);
	}
	FOR(i,N-1) {
		cin>>x>>y;
		B[x-1].push_back(y-1);
		B[y-1].push_back(x-1);
	}
	ret=N-1;
	dfs(0,-1,0);
	cout<<ret-ma<<endl;
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}