6

using System;
using System.Collections.Generic;

public class ChessBoard {
    public static void Main() {
        int n = int.Parse(Console.ReadLine().Trim());
        char[,] board = new char[n, n];
        (int, int) start = (0, 0), finish = (0, 0);

        for (int i = 0; i < n; i++) {
            string line = Console.ReadLine().Trim();
            for (int j = 0; j < n; j++) {
                board[i, j] = line[j];
                if (board[i, j] == 'S') start = (i, j);
                else if (board[i, j] == 'F') finish = (i, j);
            }
        }

        int result = BFS(board, start, finish, n);
        Console.WriteLine(result);
    }

    private static int BFS(char[,] board, (int, int) start, (int, int) finish, int n) {
        var directionsKing = new int[,] { {1, 0}, {-1, 0}, {0, 1}, {0, -1}, {1, 1}, {1, -1}, {-1, 1}, {-1, -1} };
        var directionsKnight = new int[,] { {1, 2}, {1, -2}, {-1, 2}, {-1, -2}, {2, 1}, {2, -1}, {-2, 1}, {-2, -1} };
        var queue = new Queue<(int, int, char, int)>();
        var visited = new HashSet<(int, int, char)>();

        queue.Enqueue((start.Item1, start.Item2, 'K', 0)); // Start as a knight
        visited.Add((start.Item1, start.Item2, 'K'));

        while (queue.Count > 0) {
            var (x, y, type, moves) = queue.Dequeue();
            if (x == finish.Item1 && y == finish.Item2) return moves;

            int[,] directions = type == 'K' ? directionsKnight : directionsKing;

            for (int i = 0; i < directions.GetLength(0); i++) {
                int newX = x + directions[i, 0];
                int newY = y + directions[i, 1];
                if (newX >= 0 && newY >= 0 && newX < n && newY < n && board[newX, newY] != 'W') {
                    char newType = type;
                    if (board[newX, newY] == 'K') newType = 'K';
                    else if (board[newX, newY] == 'G') newType = 'G';

                    if (!visited.Contains((newX, newY, newType))) {
                        visited.Add((newX, newY, newType));
                        queue.Enqueue((newX, newY, newType, moves + 1));
                    }
                }
            }
        }

        return -1;
    }
}