Suppose you have an algorithm that inputs a formula of propositional logic and outputs eithere SAT or UNSAT. The algorithm runs in polynomial time and gives the correct answer with probablity at least 2/3 on any input. SHOW how to obtain a polynomial-time algorithm for the propositional satisfiability problem that outputs either SAT or UNSAT on all inputs, is always correct when it returns SAT, and is correct with probability 2/3 on all inputs.