import std.algorithm, std.array, std.container, std.range;
import std.numeric, std.math, std.bigint, std.bitmanip, std.random;
import std.string, std.conv, std.stdio, std.typecons;

enum Game { NA, NotYet, Win, Lose }
alias Tuple!(int, int) pos;

void main()
{
  auto n = readln.chomp.to!int;
  auto tij = iota(n).map!((i) {
    return readln.chomp.map!((c) {
      switch (c) {
      case '#': return Game.NA;
      case '-': return Game.NotYet;
      case 'o': return Game.Win;
      case 'x': return Game.Lose;
      default: assert(0);
      }
    }).array;
  }).array;

  pos[] ai;
  foreach (i; 0..n)
    foreach (j; i + 1..n)
      if (tij[i][j] == Game.NotYet)
        ai ~= pos(i, j);

  if (!ai.empty) {
    auto min = n;
    foreach (i; 0..2 ^^ ai.length) {
      auto b = bitsSet(i);
      auto uij = tij.dup.map!(dup).array;
      foreach (j, a; ai) {
        uij[a[0]][a[1]] = b.canFind(j) ? Game.Win : Game.Lose;
        uij[a[1]][a[0]] = b.canFind(j) ? Game.Lose : Game.Win;
      }
      auto r = calcRank(uij);
      if (r < min) min = r;
    }

    writeln(min);
  } else {
    writeln(calcRank(tij));
  }
}

int calcRank(Game[][] tij)
{
  auto wi = tij.map!(a => a.count!(b => b == Game.Win)).array;
  auto w = wi.front;
  auto x = wi.sort!("a > b").uniq.array;
  return x.until(w).array.length.to!int + 1;
}