An integer is called parity-monotonic if its decimal representation a_{1} a_{2} a_{3} \ldots a_{k}
satisfies a_{i}<a_{i+1} if a_{i} is odd, and a_{i}>a_{i+1} if a_{i} is even. How many four-digit parity-monotonic integers are there?
An integer is called parity-monotonic if its decimal representation a_{1} a_{2} a_{3} \ldots a_{k}
satisfies a_{i}<a_{i+1} if a_{i} is odd, and a_{i}>a_{i+1} if a_{i} is even. How many four-digit parity-monotonic integers are there?