#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; typedef long long int lint; typedef pair IP; typedef pair LLP; typedef pairCP; #define rep(i, n) for (int i = 0; i < n; i++) #define repr(i, n) for (int i = n; i >= 0; i--) #define sort(v) sort((v).begin(), (v).end()) #define reverse(v) reverse((v).begin(), (v).end()) #define upper(v,hoge) upper_bound(v.begin(),v.end(),hoge) #define lower(v,hoge) lower_bound(v.begin(),v.end(),hoge) #define llower(v,hoge) *lower_bound(v.begin(), v.end(), hoge) #define lupper(v,hoge) *upper_bound(v.begin(), v.end(), hoge) int main() { int N; cin >> N; vectorA(N); vectorB(N); rep(i, N) { cin >> A[i] >> B[i]; } setS; rep(i, N) { S.insert(A[i]); } rep(i, N) { if (!S.count(B[i])) { cout << B[i] << endl; S.insert(B[i]); } } }