Created attachment 80 [details] The image shows a piece disappeared after an invalid input The program still removes the start move piece if it is invalid which results in the wrong total pieces number. Steps to reproduce: 1. Start the game. 2. Select a piece that is invalid. Actual outcome: 1. The program prints "Not valid start move, please input again." 2. The selected piece is removed by the program. Expected outcome: 1. The program prints "Not valid start move, please input again." 2. The selected piece is not influenced and the program asks for another valid input.