package main

import (
	"fmt"
)
import (
	"bufio"
	"os"
	"strconv"
	"strings"
)

func main() {

	N, _ := strconv.Atoi(nextLine())
	var check = make([]bool, N)
	fill(check, true)
	for i := 0; i < N; i++ {
		line := nextLine()
		elements := strings.Split(line, " ")
		for j := 0; j < N; j++ {
			if elements[j] == "-" {
				continue
			}
			if "nyanpass" != elements[j] {
				check[j] = false
			}
		}
	}
	count := 0
	last := -1
	for j := 0; j < N; j++ {
		if check[j] {
			count++
			last = j + 1
		}
	}
	if count == 1 {
		fmt.Println(last)
	} else {
		fmt.Println(-1)
	}

}

func fill(arr []bool, v bool) {
	for i := 0; i < len(arr); i++ {
		arr[i] = v
	}
}

var s = bufio.NewScanner(os.Stdin)

func nextLine() string {
	s.Scan()
	return s.Text()
}