thanks, I've add:
"...no two nodes at the same crossroad".

good luck
mima

Are there any conditions on the coordinates for the nodes ? Is "-1 -2" a valid location, what is the maximal coordinate ?
I have been checking that, when I ouput something, it matches all the conditions, but still I get WA

(Btw, I think that we should get 0 point when a solution is not valid, instead of WA, and reserve WA for malformed output only.)

thanks! I add the restrictions to the values of x and y coordinates (between 0 and 100) - they were always like this, some of the earlier versions of the problem have got it, but later I've "lost" it....

good luck!

[hmm, I thought about this, but it's hard to find an error in such a case...what't the opinion of other contestants?]