ACPC10A - What’s Next : Classical

#The solution in Python 3 is as follows:

import sys
while 1:
    a, b, c = map(int,sys.stdin.readline().split())
    if a == 0 and b == 0 and c == 0:
        break
    elif b - a == c - b:
        print ("AP", c + (b - a))               #next term for AP sequences
    elif b/a == c/b:
        print ("GP", c * (b//a))                #next term for GP sequences


#Keep visiting for more solutions of SPOJ problems in Python 3.Thank you!!!