Movement

Consider the following game. There is a 1 \times 2n board with cells numbered $\mathrm{1..2}n$ from left to right. At the start, $n$ tokens are placed in the rightmost positions of the board. All other cells are initially empty.

Alice and Bob take turns making moves: on each move, any token may be moved to the adjacent cell to the left, if that cell is unoccupied. The player who cannot make a move loses the game.

After many games, Alice and Bob observed that the result of the game depends only on $n$. However, they are not certain and decide to experimentally verify their conjecture for some $n$. Each game lasts $1$ minute. You are to compute how much time (in minutes) they need to verify their conjecture experimentally.