#include <bits/stdc++.h>
using namespace std;

char S[ 6 ][ 10 ];
bool b[ 6 ][ 6 ];
int X[ 20 ];
int Y[ 20 ];
int iBlank;
int N;

void Set( const int iNum )
{
int i;
int n;
bool bWin;

	n = iNum;
	for( i = 0; i < iBlank; i++ )
	{
		bWin = (bool) ( n % 2 );
		b[ Y[ i ] ][ X[ i ] ] = bWin;
		b[ X[ i ] ][ Y[ i ] ] = ! bWin;
		n /= 2;
	}
}

int Count()
{
int i;
int j;
int k;
int iWin[ 6 ];
int iPlayer;
int iCnt;

	iPlayer = 0;
	for( j = 0; j < N; j++ )
	{
		if( b[ 0 ][ j ] ) iPlayer++;
	}

	iCnt = 1;
	for( i = 1; i < N; i++ )
	{
		iWin[ i ] = 0;
		for( j = 0; j < N; j++ )
		{
			if( b[ i ][ j ] ) iWin[ i ]++;
		}

		if( iPlayer >= iWin[ i ] ) continue;
		for( k = 1; k < i; k++ )
		{
			if( iWin[ k ] == iWin[ i ] ) break;
		}

		if( k == i ) iCnt++;
	}

	return iCnt;
}

int main()
{
int i;
int j;
int a;
int iMax;
int iLoop;

	cin >> N;
	for( i = 0; i < N; i++ ) cin >> S[ i ];

	iLoop = 1;
	iBlank = 0;
	for( i = 0; i < N; i++ )
	{
		for( j = 0; j < N; j++ )
		{
			if( i == j ) continue;
			switch( S[ i ][ j ] )
			{
			case 'o':
				b[ i ][ j ] = true;
				
				break;
			case '-':
				if( j > i )
				{
					X[ iBlank ] = j;
					Y[ iBlank ] = i;
					iBlank++;
					iLoop *= 2;
				}
			}
		}
	}

	iMax = N;
	for( i = 0; i < iLoop; i++ )
	{
		Set( i );
		if( iMax > ( j = Count() ) ) iMax = j;
	}

	cout << iMax << endl;

	return 0;
}