Problem D
Digit Product

Consider a positive integer $x$. Multiply its nonzero digits and you get another integer $y$. Repeating this process, you eventually arrive at a single digit between $1$ and $9$. Write a program that reads $x$ and outputs the resulting digit.

Input

An integer $x$ with $10\le x\le 1000$.

Output

Print a digit between $1$ and $9$, the result of repeatedly multiplying the nonzero digits of $x$ as described above.

Explanation of Sample Inputs

In Sample Input $1$, we have $x=808$. Multiplying $8$ and $8$, we arrive at $64$. Then we get $6\cdot 4=24$, and finally $2\cdot 4=8$, which is the sample output.

In Sample Input $2$, there is only a single nonzero digit, $2$. The product of all digits in a set containing only a single element is the digit itself. Thus the answer is $2$.

808

8

20

2