Russian President Dmitry Medvedev on Wednesday said it would be irresponsible to change existing gas supply contracts between Russia and Ukraine, according to Reuters. We have signed a treaty this year for 10 years … I think that proposals to change them are irresponsible, Medvedev said in comments broadcast live on television channel Vesti-24. Despite talk that something is happening, that the (Ukrainian) president is not working, the Ukrainians are paying every month and this makes me happy, Medvedev said.