for a in ['A', 'B', 'C', 'D', 'E']: for b in ['A', 'B', 'C', 'D', 'E']: for c in ['A', 'B', 'C', 'D', 'E']: for d in ['A', 'B', 'C', 'D', 'E']: print(a, b, c, d)