import strutils, sequtils, algorithm
proc input: auto = stdin.readLine

let N = input().parseInt
var dic = newSeq[string](N)
dic.fill("")

for i in 0 ..< N:
  let A = input().split

  for j, a in A:
    dic[j] &= a
    if i != A.high: dic[j] &= ", "

for i, v in dic:
  dic[i] = $(v.count("nyanpass") + 1)

if dic.count($N) == 1:
  echo dic.find($N) + 1
else:
  echo -1