/* 祝・メンテ後初提出 */
package problems8;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

class Pair<A, B> {
    public final A first;
    public final B second;

    private Pair(A first, B second) {
        this.first = first;
        this.second = second;
    }

    public static <A, B> Pair<A, B> of(A first, B second) {
        return new Pair<>(first, second);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Pair<?, ?> pair = (Pair<?, ?>) o;
        return !(first != null ? !first.equals(pair.first) : pair.first != null) &&
                !(second != null ? !second.equals(pair.second) : pair.second != null);
    }

    @Override
    public int hashCode() {
        int result = first != null ? first.hashCode() : 0;
        result = 31 * result + (second != null ? second.hashCode() : 0);
        return result;
    }

    @Override
    public String toString() {
        return "Pair{" + "first=" + first + ", second=" + second + '}';
    }
}

public class Main {

    public void run() throws IOException {
        int N = io.nextInt();

        int[] wins = new int[N];
        List<Pair<Integer, Integer>> gs = new ArrayList<>();

        for (int i = 0; i < N; i++) {
            char[] n = io.next();
            for (int j = 0; j < N; j++) {
                char c = n[j];
                if (c == 'o') {
                    wins[i]++;
                }
                else if (c == '-' && i < j) {
                    gs.add(Pair.of(i, j));
                }
            }
        }

        int ans = Integer.MAX_VALUE;
        int[] w2 = new int[N];
        int[] cs = new int[N];
        for (int i = 0; i < (1 << gs.size()); i++) {
            for (int j = 0; j < N; j++) {
                w2[j] = cs[j] = 0;
            }
            for (int j = 0; j < gs.size(); j++) {
                int j1 = 1 << j;
                if ((i & j1) != 0) {
                    w2[gs.get(j).first]++;
                }
                else {
                    w2[gs.get(j).second]++;
                }
            }

            for (int j = 0; j < N; j++) {
                cs[w2[j] + wins[j]]++;
            }
            int c0 = 1;
            for (int j = w2[0] + wins[0] + 1; j < N; j++) {
                if (cs[j] > 0) {
                    c0++;
                }
            }
            ans = Integer.min(ans, c0);
        }
        System.out.println(ans);
    }

    // @formatter:off
    private static final int mod = (int) 1e9 + 7;
    final IOFast io = new IOFast();

    void main() throws IOException { try { run(); } catch (RuntimeException ignore) { } finally { io.out.flush(); } }
    public static void main(String[] args) throws IOException { new Main().main(); }

    public static String dtos(double x, int n) {
        StringBuilder sb = new StringBuilder();
        if (x < 0) {
            sb.append('-');
            x = -x;
        }
        x += Math.pow(10, -n) / 2;
        sb.append((long) x);
        sb.append(".");
        x -= (long) x;
        for (int i = 0; i < n; i++) {
            x *= 10;
            sb.append((int) x);
            x -= (int) x;
        }
        return sb.toString();
    }

    public static class IOFast {
        private BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        private PrintWriter out = new PrintWriter(System.out);

        void setFileIn(String ins) throws IOException { in.close(); in = new BufferedReader(new FileReader(ins)); }
        void setFileOut(String outs) throws IOException { out.flush(); out.close(); out = new PrintWriter(new FileWriter(outs)); }
        void setFileIO(String ins, String outs) throws IOException { setFileIn(ins); setFileOut(outs); }

        private static int pos, readLen;
        private static final char[] buffer = new char[1024 * 8];
        private static char[] str = new char[500*8*2];
        private static boolean[] isDigit = new boolean[256];
        private static boolean[] isSpace = new boolean[256];
        private static boolean[] isLineSep = new boolean[256];

        static { for(int i = 0; i < 10; i++) { isDigit['0' + i] = true; } isDigit['-'] = true; isSpace[' '] = isSpace['\r'] = isSpace['\n'] = isSpace['\t'] = true; isLineSep['\r'] = isLineSep['\n'] = true; }
        public int read() throws IOException { if(pos >= readLen) { pos = 0; readLen = in.read(buffer); if(readLen <= 0) { throw new RuntimeException(); } } return buffer[pos++]; }
        public int nextInt() throws IOException { int len = 0; str[len++] = nextChar(); len = reads(len, isSpace); int i = 0; int ret = 0; if(str[0] == '-') { i = 1; } for(; i < len; i++) ret = ret * 10 + str[i] - '0'; if(str[0] == '-') { ret = -ret; } return ret; }
        public long nextLong() throws IOException { int len = 0; str[len++] = nextChar(); len = reads(len, isSpace); int i = 0; long ret = 0; if(str[0] == '-') { i = 1; } for(; i < len; i++) ret = ret * 10 + str[i] - '0'; if(str[0] == '-') { ret = -ret; } return ret; }
        public char nextChar() throws IOException { while(true) { final int c = read(); if(!isSpace[c]) { return (char)c; } } }
        int reads(int len, boolean[] accept) throws IOException { try { while(true) { final int c = read(); if(accept[c]) { break; } if(str.length == len) { char[] rep = new char[str.length * 3 / 2]; System.arraycopy(str, 0, rep, 0, str.length); str = rep; } str[len++] = (char)c; } } catch(RuntimeException e) { ; } return len; }
        public char[] nextLine() throws IOException { int len = 0; str[len++] = nextChar(); len = reads(len, isLineSep); try { if(str[len-1] == '\r') { len--; read(); } } catch(RuntimeException e) { ; } return Arrays.copyOf(str, len); }
        public String nextString() throws IOException { return new String(next()); }
        public char[] next() throws IOException { int len = 0; str[len++] = nextChar(); len = reads(len, isSpace); return Arrays.copyOf(str, len); }
        public double nextDouble() throws IOException { return Double.parseDouble(nextString()); }
        public long[] nextLongArray(final int n) throws IOException { final long[] res = new long[n]; for(int i = 0; i < n; i++) { res[i] = nextLong(); } return res; }
        public int[] nextIntArray(final int n) throws IOException { final int[] res = new int[n]; for(int i = 0; i < n; i++) { res[i] = nextInt(); } return res; }
        public int[][] nextIntArray2D(final int n, final int k) throws IOException { final int[][] res = new int[n][]; for(int i = 0; i < n; i++) { res[i] = nextIntArray(k); } return res; }
        public int[][] nextIntArray2DWithIndex(final int n, final int k) throws IOException { final int[][] res = new int[n][k+1]; for(int i = 0; i < n; i++) { for(int j = 0; j < k; j++) { res[i][j] = nextInt(); } res[i][k] = i; } return res; }
        public double[] nextDoubleArray(final int n) throws IOException { final double[] res = new double[n]; for(int i = 0; i < n; i++) { res[i] = nextDouble(); } return res; }
    }
    // @formatter:on
}