2013 - 2012 * {2011 - 2010 : [2009 - 2008 : (2007 - 2006 * x)]} = 1
2012 * {2011 - 2010 : [2009 - 2008 : (2007 - 2006 * x)]} = 2012
2011 - 2010 : [2009 - 2008 : (2007 - 2006 * x)] = 1
2010 : [2009 - 2008 : (2007 - 2006 * x)] = 2010
2009 - 2008 : (2007 - 2006 * x) = 1
2008 : (2007 - 2006 * x) = 2008
2007 - 2006 * x = 1
2006 * x = 2006
x = 1