class Integer
    def gcd(b)
        a=self
        b,a=a,b if(a<b)
        until b.zero?
            a,b,q,r = b,a%b,*a.divmod(b)
            yield a,b,q,r if block_given?
        end
        a
    end
    def gcd_tex(b)
        puts "a&b\\\\\\hline"
        self.gcd(b) do |a,b|
            puts "#{a}&#{b}#{b.zero? ? "" : "\\\\"}"
        end
    end
    def xgcd_tex(b)
        puts "a&b&q&r\\\\\\hline"
        self.gcd(b) do |a,b,q,r|
            puts "#{a}&#{b}&#{q}&#{r}#{b.zero? ? "" : "\\\\"}"
        end
    end
end