Karen arrive school math test today the test basic addition subtraction unfortunately teacher busy write task Codeforces round time actual test so question test worth pointsThere n integer write row Karen alternately add subtract pair adjacent integer write sum difference row she repeat process value row integer remain the operation additionnote end previous row add integer start row subtract vice versaThe teacher simply look integer correct Karen get perfect score get zero testKaren study test scare mistake cause final answer wrong if process follow number expect write rowsince number large output nonnegative remainder divide 1097