Japanese crossword «Gauss Karl Friedrich»

I have always wanted to visit Koeninsberg and cross its 7 bridges. But when refreshing my memory about the bridges problem, I found out that Koeninsberg is now known as Kaliningrad and that there are only 5 bridges nowadays. But interestingly enough for computer scientists like myself, there is still no way to cross the bridges exactly once to complete a cycle. I like to think that the mayor who took the 2 bridges down had left the problem untouched on purpose.