п»ї#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <string>

using namespace std;

int main() {
    ifstream input("input.txt");
    ofstream output("output.txt");

    int size;
    int i = 0;

    input >> size;

    if (size == 1) {
        output << 0;
        return 0;
    }

    vector<vector<bool>> isPassable(size, vector<bool>(size, false));
    vector<vector<int>> isChecked(size, vector<int>(size, 0));

    string temp;
    getline(input, temp);

    while (!input.eof()) {
        getline(input, temp);
        if (temp == "") break;
        for (int j = 0; j < size; j++) {
            if (temp[j] == '.') {
                isPassable[i][j] = true;
            }
        }
        ++i;
    }

    if (!isPassable[0][0]) {
        output << -1;
        return 0;
    }

    queue <pair<int, int>> graph;
    graph.push(make_pair(0, 0));

    while (!graph.empty()) {
        pair<int, int> point = graph.front();
        graph.pop();
        if (point.first != 0 && isPassable[point.first - 1][point.second] && isChecked[point.first - 1][point.second] == 0) {
            isChecked[point.first - 1][point.second] = isChecked[point.first][point.second] + 1;
            graph.push(make_pair(point.first - 1, point.second));
        }
        if (point.second != 0 && isPassable[point.first][point.second - 1] && isChecked[point.first][point.second - 1] == 0) {
            isChecked[point.first][point.second - 1] = isChecked[point.first][point.second] + 1;
            graph.push(make_pair(point.first, point.second - 1));
        }
        if (point.first != size - 1 && isPassable[point.first + 1][point.second] && isChecked[point.first + 1][point.second] == 0) {
            isChecked[point.first + 1][point.second] = isChecked[point.first][point.second] + 1;
            graph.push(make_pair(point.first + 1, point.second));
        }
        if (point.second != size - 1 && isPassable[point.first][point.second + 1] && isChecked[point.first][point.second + 1] == 0) {
            isChecked[point.first][point.second + 1] = isChecked[point.first][point.second] + 1;
            graph.push(make_pair(point.first, point.second + 1));
        }
    }

    if (isChecked[size - 1][size - 1] == 0) {
        output << -1;
        return 0;
    }

    output << isChecked[size - 1][size - 1];
    input.close();
    output.close();

    return 0;
}