import System.Environment
(%)=(,)
a n=[x%y|x<-n,y<-n,x<y]
s[]=[[]]
s[m]=[[m]]
s((x,y):(z,w):l)|x==z||x==w||y==z||y==w=s(x%y:l++[z%w])|0<1=[x%y:q|q<-s(z%w:l)]
aW1wb3J0IFN5c3RlbS5FbnZpcm9ubWVudAooJSk9KCwpCmEgbj1beCV5fHg8LW4seTwtbix4PHldCnNbXT1bW11dCnNbbV09W1ttXV0KcygoeCx5KTooeix3KTpsKXx4PT16fHx4PT13fHx5PT16fHx5PT13PXMoeCV5OmwrK1t6JXddKXwwPDE9W3gleTpxfHE8LXMoeiV3OmwpXQptYWluPWRvIGc8LWdldEFyZ3M7cHJpbnQkaGVhZCRzJGFbMS4ucmVhZCRnISEwOjpJbnRd