SkyLine
 
 
You have been hired for the most recent digital imaging company in
Imagine Land Valley, and your very first job is to write a rendering program
for artificial skylines. A skyline is a drawing of a row of buildings (no more
than 40) of variable height (between 1 and 100). Given a number of buildings
and the corresponding height, you should draw the skyline using ASCII
characters, as the following example shows:
 
              
XX   XXXXXXX  XX X   XXXX
              
XX X XXXXXXX XXX XX  XXXX
           
X  XX X XXXXXXX XXX XX  XXXX
           
X XXX X XXXXXXX XXX XX  XXXX
           
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Input
The input consists an integer N, specifying the number of buildings, which also denotes the width of
the skyline, followed by a sequence of N lines containing, as an integer, the height of each building to be
plotted. 
 
Output
The plotting of the skyline, drawn horizontally as show in the example
above, using just  the character "X" and spaces. The output will consist in L+1 strings, all of length N, and where L is the height of the tallest
building. The output represents the skyline as follows: on the bottom (last
line), the ground is represented by a string consisting just of "X" characters. On top of it, in each column i there must be a column of Hi characters "X",  where Hi is the height of the ith building
in the input.
 
Sample Input
6
1
5
5
2
4
4
 
Sample Output
 XX   
 XX XX
 XX XX
 XXXXX
XXXXXX
XXXXXX