C++ :

#include<bits/stdc++.h>
using namespace std;
int n;
string s, tmp;
struct dictionary {
	string a, b;
} Q[102];
int main() {
	cin >> n;
	for (int i = 1; i <= n; i++)cin >> Q[i].a >> Q[i].b;
	cin >> s;
	s += '0';
	for (int i = 0; i < s.length(); i++) {
		if (s[i] >= 'a' && s[i] <= 'z')tmp += s[i];
		else {
			if (s[i - 1] >= 'a' && s[i - 1] <= 'z') {//在多重标点时不用判断
				int flag = 0;
				for (int j = 1; j <= n; j++) {
					if (tmp == Q[j].a) {
						tmp = Q[j].b;
						flag = 1;
						break;
					}
				}
				if (flag == 0)cout << "UNK";
				else {
					cout << tmp;
				}
				tmp = "";//将字符串清空
			}
			if (s[i] != '0')cout << s[i];
		}
	}
	return 0;
}