import Data.List (transpose, elemIndices)

findRenchon :: [[String]] -> Int
findRenchon xs
    | length cands == 1 = head cands
    | otherwise         = -1
    where
        cands = map (+ 1) $ elemIndices (length xs - 1) $
            map (length . elemIndices "nyanpass") xs

main :: IO ()
main = getLine >> getContents >>= print . findRenchon . transpose .
    map words . lines