using System;
using System.Linq;
using System.Collections.Generic;

namespace Contest
{
    class Program
    {
        static void Main(string[] args)
        {
            AGC014.C();
        }

        class AGC014
        {
            public static void A()
            {
                var A = Read.Long();
                var B = Read.Long();
                var C = Read.Long();
                if (A == B && B == C) { Console.WriteLine(-1); return; }
                int max = 1;
                var d1 = A - B;
                var d2 = A - C;
                for (int i = 0; i < 30; ++i)
                {
                    var n = 1L << i;
                    if (d1 % n == 0 && d2 % n == 0)
                    {
                        max = i;
                    }
                }
                Console.WriteLine(max);
            }
            public static void B()
            {
                var N = Read.Int();
                var M = Read.Int();
                var AB = Read.TupleInt(M);
                int[] count = new int[N + 1];
                foreach(var ab in AB)
                {
                    count[ab.Item1]++;
                    count[ab.Item2]++;
                }
                Console.WriteLine(count.Count(x => x % 2 == 1) == 0 ? "YES" : "NO");
            }
            public static void C()
            {
                var H = Read.Int();
                var W = Read.Int();
                var K = Read.Int();
                var A = new bool[H + 2, W + 2];
                int Sh = -1, Sw = -1;
                for (int h = 0; h < H; ++h)
                {
                    var str = Read.Str();
                    for (int w = 0; w < W; ++w)
                    {
                        switch (str[w])
                        {
                            case '.': A[h + 1, w + 1] = true; break;
                            case 'S': A[h + 1, w + 1] = true; Sh = h + 1; Sw = w + 1; break;
                        }
                    }
                }
                var dist = new int[H + 2, W + 2];
                for (int h = 0; h < H + 2; ++h)
                {
                    for (int w = 0; w < W + 2; ++w)
                    {
                        dist[h, w] = -1;
                    }
                }
                var dx = new int[] { 0, 1, 0, -1 };
                var dy = new int[] { 1, 0, -1, 0 };
                Queue<Tuple<int, int>> queue = new Queue<Tuple<int, int>>();
                queue.Enqueue(new Tuple<int, int>(Sh, Sw));
                dist[Sh, Sw] = 0;
                while (queue.Count > 0)
                {
                    var t = queue.Dequeue();
                    if (dist[t.Item1, t.Item2] >= K) { continue; }
                    for(int i = 0; i < 4; ++i)
                    {
                        var x = t.Item1 + dx[i];
                        var y = t.Item2 + dy[i];
                        if(A[x,y] && dist[x, y] < 0)
                        {
                            dist[x, y] = dist[t.Item1, t.Item2] + 1;
                            queue.Enqueue(new Tuple<int, int>(x, y));
                        }
                    }
                }
                var min = 100000000;
                for (int h = 0; h < H + 2; ++h)
                {
                    for (int w = 0; w < W + 2; ++w)
                    {
                        if(dist[h, w] >= 0)
                        {
                            var d = Math.Min(h - 1, Math.Min(H - h, Math.Min(w - 1, W - w)));
                            min = Math.Min(min, d);
                        }
                    }
                }
                Console.WriteLine(1 + (min + K - 1) / K);
            }
            public static void D()
            {
                var N = Read.Int();
                var Adj = Read.AdjacencyList(N, N - 1);
                var dist = Graph.CalcDistance_OnTree(Adj, N, 1);
                var order = Enumerable.Range(1, N).OrderBy(i => -dist[i]).ToArray();
                var delete = new bool[N + 1];
                foreach(var v in order)
                {
                    if (delete[v]) { continue; }
                    delete[v] = true;
                    bool ok = false;
                    foreach(var w in Adj[v])
                    {
                        if (!delete[w])
                        {
                            ok = true;
                            delete[w] = true;
                            break;
                        }
                    }
                    if (!ok)
                    {
                        Console.WriteLine("First"); return;
                    }
                }
                Console.WriteLine("Second");
            }
        }

        class Graph
        {
            public static int[] CalcDistance_OnTree(Dictionary<int, HashSet<int>> adj, int N, int start)
            {
                var dist = Enumerable.Range(0, N + 1).Select(i => -1).ToArray();
                dist[start] = 0;
                Queue<int> queue = new Queue<int>();
                queue.Enqueue(start);
                while (queue.Count > 0)
                {
                    var v = queue.Dequeue();
                    foreach (var w in adj[v])
                    {
                        if (dist[w] < 0)
                        {
                            dist[w] = dist[v] + 1;
                            queue.Enqueue(w);
                        }
                    }
                }
                return dist;
            }
        }

        static class Read
        {
            static Queue<string> queue = new Queue<string>();
            static void Enqueue() { var ss = Console.ReadLine().Split(' '); foreach (var s in ss) { queue.Enqueue(s); } }
            public static int Int() { if (queue.Count == 0) { Enqueue(); } return Convert.ToInt32(queue.Dequeue()); }
            public static long Long() { if (queue.Count == 0) { Enqueue(); } return Convert.ToInt64(queue.Dequeue()); }
            public static string Str() { if (queue.Count == 0) { Enqueue(); } return queue.Dequeue(); }
            public static int[] IntN() { return Console.ReadLine().Split(' ').Select(s => Convert.ToInt32(s)).ToArray(); }
            public static long[] LongN() { return Console.ReadLine().Split(' ').Select(s => Convert.ToInt64(s)).ToArray(); }
            public static string[] StrN() { return Console.ReadLine().Split(' '); }
            public static Tuple<int, int>[] TupleInt(int n) { List<Tuple<int, int>> list = new List<Tuple<int, int>>(); for (int i = 0; i < n; ++i) { var ab = Read.IntN(); list.Add(new Tuple<int, int>(ab[0], ab[1])); } return list.ToArray(); }
            public static Tuple<long, long>[] TupleLong(int n) { List<Tuple<long, long>> list = new List<Tuple<long, long>>(); for (int i = 0; i < n; ++i) { var ab = Read.LongN(); list.Add(new Tuple<long, long>(ab[0], ab[1])); } return list.ToArray(); }
            public static Tuple<string, string>[] TupleStr(int n) { List<Tuple<string, string>> list = new List<Tuple<string, string>>(); for (int i = 0; i < n; ++i) { var ab = Read.StrN(); list.Add(new Tuple<string, string>(ab[0], ab[1])); } return list.ToArray(); }
            public static Tuple<double, double>[] TupleDouble(int n) { List<Tuple<double, double>> list = new List<Tuple<double, double>>(); for (int i = 0; i < n; ++i) { var ab = Read.LongN(); list.Add(new Tuple<double, double>(ab[0], ab[1])); } return list.ToArray(); }
            public static long[,] LongMatrix(int r, int c)
            {
                var mat = new long[r, c];
                for (int i = 0; i < r; ++i)
                {
                    var x = Read.LongN();
                    for (int j = 0; j < c; ++j)
                    {
                        mat[i, j] = x[j];
                    }
                }
                return mat;
            }
            public static Dictionary<int, HashSet<int>> AdjacencyList(int N, int M)
            {
                Dictionary<int, HashSet<int>> dict = new Dictionary<int, HashSet<int>>();
                for (int i = 0; i <= N; ++i)
                {
                    dict.Add(i, new HashSet<int>());
                }
                for (int i = 0; i < M; ++i)
                {
                    var ab = Read.IntN();
                    dict[ab[0]].Add(ab[1]);
                    dict[ab[1]].Add(ab[0]);
                }
                return dict;
            }
            public static Dictionary<int, Dictionary<int, long>> AdjacencyListWithWeight(int N, int M)
            {
                Dictionary<int, Dictionary<int, long>> dict = new Dictionary<int, Dictionary<int, long>>();
                for (int i = 0; i <= N; ++i)
                {
                    dict.Add(i, new Dictionary<int, long>());
                }
                for (int i = 0; i < M; ++i)
                {
                    var ab = Read.IntN();
                    dict[ab[0]].Add(ab[1], ab[2]);
                    dict[ab[1]].Add(ab[0], ab[2]);
                }
                return dict;
            }
        }
    }
}


Measured memory_bytes: 20444