Given an integer representing a $7-$digit phone number, excluding the area code, output the prefix and line number, separated by a hyphen.

Ex: If the input is:

$5551212$

the output is:

$555-1212$

Hint: Use $\%$ to get the desired rightmost digits. Ex: The rightmost $2$ digits of $572$ is gotten by $572\%100,$ which is $72.$

Hint: Use $/$ to shift right by the desired amount. Ex: Shifting $572$ right by $2$ digits is done by $572/100,$ which yields $5.($Recall integer division discards the fraction$).$

For simplicity, assume any part starts with a non$-$zero digit. So $011-9999$ is not allowed.