why c# keyword showing compiler error

Sir chef jump program is running on my system but here its showing compiler error in keyword “using” of c# lang.

What type of error are you getting?
you may refer to sample solution:
http://www.codechef.com/wiki/sample-solutions#C-2.

please check you are wriing the “using” keyword at the top of your code page (outside the namespace block)

//