// ﾅﾆｿﾚｲﾐﾜｶﾝﾅｲ

#include <cstdio>
#include <vector>
#include <algorithm>

int N;
char result[6][6];
int win[6];

int rec(int x, int y){
    if(y == N-1){
        std::vector<int> v(win, win+N);
        std::sort(v.begin(), v.end());
        v.erase(std::unique(v.begin(), v.end()), v.end());

        return v.size() - (std::lower_bound(v.begin(), v.end(), win[0]) - v.begin());
    }

    int nx, ny;
    if(x+1 == N){
        ny = y + 1;
        nx = ny + 1;
    }else{
        ny = y;
        nx = x + 1;
    }

    int res = N;
    if(result[y][x] == '-'){
        win[x] += 1;
        res = std::min(res, rec(nx, ny));
        win[x] -= 1;

        win[y] += 1;
        res = std::min(res, rec(nx, ny));
        win[y] -= 1;
    }else{
        res = std::min(res, rec(nx, ny));
    }

    return res;
}

int main(){
    scanf("%d", &N);

    for(int i=0;i<N;i++){
        scanf("%*c");
        for(int j=0;j<N;j++){
            scanf("%c", &result[i][j]);

            if(result[i][j] == 'o'){win[i] += 1;}
        }
    }

    printf("%d\n", rec(1, 0));
}