#include<string.h>
 
int x(int a[][7],int n,int t){
int b[6]={},c[7][7]={},i=0,j=0,f=1,w,l;
if(t==0){
for(i=0;i<n;i++)for(j=0;j<n;j++)if(a[i][j]=='o')b[i]++;
for(i=n;i>2;i--)for(j=2;j<i;j++)if(b[j-1]>b[j])b[j-1]^=b[j]^=b[j-1]^=b[j];
for(i=1;i<n;i++)if(b[i]>b[0]&&b[i-1]!=b[i])f++;
return f;
}
for(i=-1;f&&++i<n;)for(j=i;f&&++j<n;)if(a[i][j]=='-')f--;
memcpy(c,a,196);
c[i][j]='o';c[j][i]='x';w=x(c,n,t-1);
c[i][j]='x';c[j][i]='o';l=x(c,n,t-1);
return w<l?w:l;
}
 
int main(){
int n,a[7][7]={},t=0,i,j;
scanf("%d\n",&n);
for(i=0;i<n;i++){
for(j=0;j<n;j++)a[i][j]=getchar(),a[i][j]-'-'||t++;
getchar();
}
t/=2;
printf("%d",x(a,n,t));
return 0;
}