2 1
first
second
first second 10
first first
first first
second first
first first
样例输出 #1
10
样例输入 #2
10 15 stockholm amsterdam london berlin copenhagen oslo helsinki dublin reykjavik brussels oslo stockholm 415 stockholm helsinki 396 oslo london 1153 oslo copenhagen 485 stockholm copenhagen 522 copenhagen berlin 354 copenhagen amsterdam 622 helsinki berlin 1107 london amsterdam 356 berlin amsterdam 575 london dublin 463 reykjavik dublin 1498 reykjavik oslo 1748 london brussels 318 brussels amsterdam 173 stockholm amsterdam oslo london reykjavik dublin brussels helsinki
