package main

import . "fmt"

func main() {
	var n int
	Scan(&n)
	b:=make([]int,n)
	for _=range b {
		for i:=range b {
			var a string
			Scan(&a)
			if a=="nyanpass" {
				b[i]=1
			}
		}
	}
	c:=0
	k:=0
	for i,v:=range b {
		c+=v
		k+=(i+1)*v
	}
	if c!=1 {
		Println(-1)
		return
	}
	Println(k)
}