import Data.List
f n x=if null x then 0 else if even x then f (n+1) (x`div`2) else n
main=do
 q<-map read.words<$>getLine :: IO [Int]
 let s=sort q
     p=map(f 0)[s!!1-head s,last s-head s,last s-s!!1]
 print$if all(==(0))p && even(head s) then -1 else minimum p