Decode the message to find the flag

A B (2726 2310 3000 2790 641 597 855 2412 1230 1632 119 2570 487 119 745 1313 884 884 1313 2412 1230 1516) 2753 17 F G H I J K L M 3233 O P Q R S T U V W X Y Z