10 DEF FN MOD(X) = X - INT (X / A) * A
20 LM = 0: INPUT "GIVE N AND K (N,K): ";N,K
30 IF N < 1 or K < 1 THEN GOTO 20
40 FOR A = 1 TO N: LM = FN MOD(LM + K): NEXT A
50 PRINT "N = ";N;", K = ";K;", SURVIVOR: ";LM