Cute Common Divisor

Vasya is very good at counting crows outside the window during math class. Today was an unusual day, since there were a lot of crows. On top of that, there were two kinds: white and black. By the middle of the lesson Vasya finished counting, and outside the window there were $a$ white crows and $b$ black crows.

Since an unbearably long time remained until the end of the lesson, Vasya decided to listen to what the teacher was saying. At that moment the teacher was explaining what the greatest common divisor of two numbers is. Vasya is a very talented boy and understood it right away. He instantly computed the greatest common divisor of $a$ and $b$.

After that he came up with a new term: cute common divisor. Vasya decided to call a positive integer $d$ a cute common divisor of $x$ and $y$ if $x$ is divisible by $d$, $y$ is divisible by $d$, and the sum of the digits of $d$ is maximal.

Help Vasya find the cute common divisor of $a$ and $b$.

The only line of the input file contains two integers $a$, $b$ ($1 \le a, b \le 10^9$).

Print the cute common divisor of $a$ and $b$ on the only line of the output file. If there are several answers, you may print any of them.