using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using static System.Console;
using static System.Math;
using static MyIO;
using static MyUtil;

public class C { public static void Main() => (new Solver()).Solve(); }

public class Solver
{
	public void Solve()
	{
		long H = GetLong();
		long W = GetLong();
		long K = GetLong();

		var grid = new char[H, W];
		(long, long) s = (-1, -1);
		for(long i = 0; i < H; i++)
		{
			var A = GetString().ToCharArray();
			for(long j = 0; j < W; j++)
			{
				grid[i, j] = A[j];
				if(A[j] == 'S')
					s = (i, j);
			}
		}

		long ans = long.MaxValue;
		var queue = new Queue<(long, long, long)>();
		var visited = new bool[H, W];
		queue.Enqueue((s.Item1, s.Item2, 0));
		visited[s.Item1, s.Item2] = true;

		var dy = new long[] { -1, 0, 1, 0 };
		var dx = new long[] { 0, -1, 0, 1 };

		while(queue.Count > 0)
		{
			var (y, x, d) = queue.Dequeue();
			
			chmin(ref ans, sdiv(y, K) + 1);
			chmin(ref ans, sdiv(H - 1 - y, K) + 1);
			chmin(ref ans, sdiv(x, K) + 1);
			chmin(ref ans, sdiv(W - 1 - x, K) + 1);

			for(long i = 0; i < 4; i++)
			{
				long ny = y + dy[i];
				long nx = x + dx[i];
				if(ny < 0 || ny >= H || nx < 0 || nx >= W || grid[ny, nx] == '#' || visited[ny, nx])
					continue;

				visited[ny, nx] = true;
				
				if(d < K)
					queue.Enqueue((ny, nx, d + 1));
			}
		}
		WriteLine(ans);
	}

	private long sdiv(long x, long y) => (x + y - 1) / y;
}

public static class MyIO
{
	private static string[] args = new string[0];
	private static int cnt = 0;
	private static IEnumerable<string> getArgs(long N) => Range(0, N).Select(_ => getArg());
	private static string getArg()
	{
		if(cnt == args.Length) { args = Console.ReadLine().Split(); cnt = 0; }
		return args[cnt++];
	}

	public static int GetInt() => int.Parse(getArg());
	public static long GetLong() => long.Parse(getArg());
	public static double GetDouble() => double.Parse(getArg());
	public static decimal GetDecimal() => decimal.Parse(getArg());
	public static string GetString() => getArg();
	public static char GetChar() => getArg()[0];
	public static int[] GetInts(long N) => getArgs(N).Select(int.Parse).ToArray();
	public static long[] GetLongs(long N) => getArgs(N).Select(long.Parse).ToArray();
	public static double[] GetDoubles(long N) => getArgs(N).Select(double.Parse).ToArray();
	public static decimal[] GetDecimals(long N) => getArgs(N).Select(decimal.Parse).ToArray();
	public static string[] GetStrings(long N) => getArgs(N).ToArray();
}

public static class MyUtil
{
	public static void chmax<T>(ref T x, T y) where T : IComparable<T> { if(x.CompareTo(y) < 0) x = y; }
	public static void chmin<T>(ref T x, T y) where T : IComparable<T> { if(x.CompareTo(y) > 0)	x = y; }
	public static void swap<T>(ref T x, ref T y) { T tmp = x; x = y; y = tmp; }
	public static long rightShift(long x, long y) => (x >> (int)y);
	public static long leftShift(long x, long y) => (x << (int)y);
	public static bool contains(long s, long x) => (rightShift(s, x) & 1L) == 1L;
	public static long gcd(long x, long y) => (y == 0) ? x : gcd(y, x % y);
	public static long lcm(long x, long y) => (x / gcd(x,y)) * y;	
	public static IEnumerable<int> Range(long start, long count) => Enumerable.Range((int)start, (int)count);
	public static void Sort(this List<string> source) => source.Sort(StringComparer.Ordinal);
}


Measured memory_bytes: 32524