Problem Statement

It is said that Renge Miyauchi (commonly known as Renchon) greets people with "nyanpass" at any time and on any occasion.
By extension, a person who greets with "nyanpass" at any time and on any occasion is called "Renchon-like".

There are $N$ villagers in the village, assigned villager numbers \(1 ～ N\).
The greeting history of the $N$ people is given as an $N \times N$ matrix $A$. $A_{ij}$ represents what villager $j$ said when villagers $i$ and $j$ greeted each other.

When exactly one person among the $N$ people is Renchon-like, we say that Renchon has been "identified".
If Renchon can be identified, output that villager number; otherwise, output -1.

Input

$N$
$A_{11}$ $A_{12}$ $\ldots$ $A_{1N}$
$A_{21}$ $A_{22}$ $\ldots$ $A_{2N}$
$\ldots$
$A_{N1}$ $A_{N2}$ $\ldots$ $A_{NN}$

• $2 \leq N \leq 100$
• $A_{ii}$ is "-" (excluding the quotation marks)
• $A_{ij}$ is a string of between 1 and 30 lowercase English letters.

Output

If Renchon can be identified, output that villager number; otherwise, output -1.

Sample

4
- nyanpass uissu ohayo
konbanwa - ohayo ohayo
ohayogozaimasu nyanpass - komachanyuuna
konnichiwa nyanpass komachanohayo -

2

3
- nyanpass ohayo
nyanpass - chicchakunaiyo
nyanpass nyanpass -

-1

3
- ohayo nyanpass
nyanpass - ohayo
nyanpass ohayo -

1

2
- ohayo
zukoo -

-1