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In the box lies a complete set of dominoes. Two players take turns picking one tile from the box and placing it on the table, attaching it to the already laid chain from either side according to the rules of dominoes. The player who cannot make the next move loses. Who will win with correct play?
Let's describe the winning strategy for Player I. Initially, he places 0:0 on the table, Player II responds with 0: $a$, then I

places the tile $a: a$. Now, II either plays $0: n$ or $a: n$. In the first case, I places the tile $n: a$ to the end containing $n$, in the second case - $n: 0$ to the same end. Then, after I's move, the ends of the chain will be 0 or $a$. The same will happen after Player II's move $0: m$ ( $a: m$ ) when I responds with $m: a$ ( $m: 0$ ). Tiles of the form $0: n$ and $a: n$ ( $n \neq 0, a$ ) are paired, so the last move will remain with the first player.

## Answer

The first player wins.