using System;
namespace AtCoder
{
    static class Solver
    {
        static IO io = new IO();

        public static void Solve()
        {
            io.ReadSplit();
            int H = io.Int();
            int W = io.Int();
            int K = io.Int();

            int[,] room = new int[H, W];
            int start_i = 0;
            int start_j = 0;
            for (int i = 0; i < H; ++i)
            {
                io.Read();
                string str = io.String();
                for (int j = 0; j < W; ++j)
                {
                    switch (str.Substring(j, 1))
                    {
                        case "#":
                            room[i, j] = -1;
                            break;
                        case ".":
                            room[i, j] = int.MaxValue;
                            break;
                        case "S":
                            room[i, j] = int.MaxValue;
                            start_i = i;
                            start_j = j;
                            break;
                    }
                }
            }

            int count = Count(room, start_i, H, start_j, W, 0, K);

            io.WriteLine((Math.Ceiling((decimal)count / K) + 1).ToString());
        }

        private static int Count(int[,] room, int i, int H, int j, int W, int k, int K)
        {
            if (i < 0) { return int.MaxValue; }
            if (i >= H) { return int.MaxValue; }
            if (j < 0) { return int.MaxValue; }
            if (j >= W) { return int.MaxValue; }
            if (room[i, j] < 0) { return int.MaxValue; }
            if (room[i, j] <= k) { return int.MaxValue; }
            int distance = Math.Min(Math.Min(i, H - i - 1), Math.Min(j, W - j - 1));
            if (k >= K) { return distance; }
            room[i, j] = k;
            return Math.Min(distance, Math.Min(Count(room, i + 1, H, j, W, k + 1, K), Math.Min(Count(room, i - 1, H, j, W, k + 1, K), Math.Min(Count(room, i, H, j + 1, W, k + 1, K), Count(room, i, H, j - 1, W, k + 1, K)))));
        }
    }
}
namespace AtCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            Solver.Solve();
        }
    }
    class IO
    {
        private string[] _Inputs;
        private int _Index;
        public void Read()
        {
            _Inputs = new string[1];
            _Inputs[0] = Console.ReadLine();
            _Index = 0;
        }
        public void ReadSplit()
        {
            _Inputs = Console.ReadLine().Split(' ');
            _Index = 0;
        }
        public string String()
        {
            return _Inputs[_Index++];
        }
        public string[] String(int xCount)
        {
            string[] rv = new string[xCount];
            Array.Copy(_Inputs, _Index, rv, 0, xCount);
            _Index += xCount;
            return rv;
        }
        public int Int()
        {
            return int.Parse(_Inputs[_Index++]);
        }
        public int[] Int(int xCount)
        {
            int[] rv = new int[xCount];
            for (int i = 0; i < xCount; ++i)
            {
                rv[i] = int.Parse(_Inputs[_Index++]);
            }
            return rv;
        }
        public long Long()
        {
            return long.Parse(_Inputs[_Index++]);
        }
        public long[] Long(int xCount)
        {
            long[] rv = new long[xCount];
            for (int i = 0; i < xCount; ++i)
            {
                rv[i] = long.Parse(_Inputs[_Index++]);
            }
            return rv;
        }
        public void Write(string xStr)
        {
            Console.Write(xStr);
        }
        public void WriteLine(string xStr)
        {
            Console.WriteLine(xStr);
        }
    }
}