unittest
{
	assert( [ "4" ].parse.expand.solve == 48 );
	assert( [ "15" ].parse.expand.solve == 675 );
	assert( [ "80" ].parse.expand.solve == 19200 );
}



import std.conv;
import std.range;
import std.stdio;
import std.typecons;

void main()
{
	stdin.byLineCopy.parse.expand.solve.writeln;
}

auto parse( Range )( Range input )
if( isInputRange!Range && is( ElementType!Range == string ) )
{
	auto r = input.front.to!( long );
	return tuple( r );
}

auto solve( long r )
{
	return 3 * r * r;
}
