Write a program to get a user$$s integer input for the number of lines $($ranging from $2$ to $9),$ and then print a triangular pattern of numbers by a nested for loop. For example, if the user$$s input is $5,$ the pattern should look like:

$1$

$12$

$123$

$1234$

$12345$

If the user$$s input is $8,$ the pattern should look like:

$1$

$12$

$123$

$1234$

$12345$

$123456$

$1234567$

$12345678$