Eliminate all letters

1. Each player can play the game in sequence, including two player battles, three player battles, and four player battles
2. Before starting the game, the gentleman forms three random letters
3. Use randomly generated letters to perform addition, subtraction, or multiplication calculations, so that the calculated results are consistent with the letters A-R
4. The player who first calculates all the letters is the winner
5. If the letters calculated in this round have already been calculated, they will not be included in the calculation result, and the next player will start the game

Note: The letters A-R represent the numbers 1-18, and the calculation of letters is the calculation of numbers, which needs to be converted by oneself