import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.InputMismatchException;
import java.util.Queue;

public class Main {
	static InputStream is;
	static PrintWriter out;
	static String INPUT = "";
	
	static void solve()
	{
		int n = ni(), m = ni(), K = ni();
		char[][] map = nm(n,m);
		int sr = -1, sc = -1;
		for(int i = 0;i < n;i++){
			for(int j = 0;j < m;j++){
				if(map[i][j] == 'S'){
					map[i][j] = '.';
					sr = i; sc = j;
				}
			}
		}
		
		int[][] ds = distMap(map, sr, sc);
		int minstep = 99999999;
		for(int i = 0;i < n;i++){
			for(int j = 0;j < m;j++){
				if(ds[i][j] <= K && (i == 0 || i == n-1) && (j == 0 || j == m-1)){
					out.println(1);
					return;
				}
				if(ds[i][j] <= K){
					int ld = Math.min(Math.min(i, n-1-i), Math.min(j, m-1-j));
					int step = (ld+K-1)/K+1;
					minstep = Math.min(minstep, step);
				}
			}
		}
		out.println(minstep);
	}
	
	public static int[][] distMap(char[][] map, int sr, int sc)
	{
		int[] dr = { 1, 0, -1, 0 };
		int[] dc = { 0, 1, 0, -1 };
		int n = map.length;
		if(n == 0)return new int[0][0];
		int m = map[0].length;
		int l = dr.length;
		int[][] d = new int[n][m];
		int I = 999999999;
		for(int i = 0;i < n;i++) {
			Arrays.fill(d[i], 999999999);
		}
		
		int B = Integer.numberOfTrailingZeros(Integer.highestOneBit(m))+1;
		Queue<Integer> q = new ArrayDeque<Integer>();
		q.add(sr<<B|sc);
		d[sr][sc] = 0;
		
		while(!q.isEmpty()){
			int cur = q.poll();
			int r = cur>>>B, c = cur&(1<<B)-1;
			for(int k = 0;k < l;k++) {
				int nr = r + dr[k];
				int nc = c + dc[k];
				if(nr >= 0 && nr < n && nc >= 0 && nc < m && map[nr][nc] == '.' && d[nr][nc] == I) { // fix
					d[nr][nc] = d[r][c] + 1;
					q.add(nr<<B|nc);
				}
			}
		}
		return d;
	}

	
	public static void main(String[] args) throws Exception
	{
		long S = System.currentTimeMillis();
		is = INPUT.isEmpty() ? System.in : new ByteArrayInputStream(INPUT.getBytes());
		out = new PrintWriter(System.out);
		
		solve();
		out.flush();
		long G = System.currentTimeMillis();
		tr(G-S+"ms");
	}
	
	private static boolean eof()
	{
		if(lenbuf == -1)return true;
		int lptr = ptrbuf;
		while(lptr < lenbuf)if(!isSpaceChar(inbuf[lptr++]))return false;
		
		try {
			is.mark(1000);
			while(true){
				int b = is.read();
				if(b == -1){
					is.reset();
					return true;
				}else if(!isSpaceChar(b)){
					is.reset();
					return false;
				}
			}
		} catch (IOException e) {
			return true;
		}
	}
	
	private static byte[] inbuf = new byte[1024];
	static int lenbuf = 0, ptrbuf = 0;
	
	private static int readByte()
	{
		if(lenbuf == -1)throw new InputMismatchException();
		if(ptrbuf >= lenbuf){
			ptrbuf = 0;
			try { lenbuf = is.read(inbuf); } catch (IOException e) { throw new InputMismatchException(); }
			if(lenbuf <= 0)return -1;
		}
		return inbuf[ptrbuf++];
	}
	
	private static boolean isSpaceChar(int c) { return !(c >= 33 && c <= 126); }
//	private static boolean isSpaceChar(int c) { return !(c >= 32 && c <= 126); }
	private static int skip() { int b; while((b = readByte()) != -1 && isSpaceChar(b)); return b; }
	
	private static double nd() { return Double.parseDouble(ns()); }
	private static char nc() { return (char)skip(); }
	
	private static String ns()
	{
		int b = skip();
		StringBuilder sb = new StringBuilder();
		while(!(isSpaceChar(b))){
			sb.appendCodePoint(b);
			b = readByte();
		}
		return sb.toString();
	}
	
	private static char[] ns(int n)
	{
		char[] buf = new char[n];
		int b = skip(), p = 0;
		while(p < n && !(isSpaceChar(b))){
			buf[p++] = (char)b;
			b = readByte();
		}
		return n == p ? buf : Arrays.copyOf(buf, p);
	}
	
	private static char[][] nm(int n, int m)
	{
		char[][] map = new char[n][];
		for(int i = 0;i < n;i++)map[i] = ns(m);
		return map;
	}
	
	private static int[] na(int n)
	{
		int[] a = new int[n];
		for(int i = 0;i < n;i++)a[i] = ni();
		return a;
	}
	
	private static int ni()
	{
		int num = 0, b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static long nl()
	{
		long num = 0;
		int b;
		boolean minus = false;
		while((b = readByte()) != -1 && !((b >= '0' && b <= '9') || b == '-'));
		if(b == '-'){
			minus = true;
			b = readByte();
		}
		
		while(true){
			if(b >= '0' && b <= '9'){
				num = num * 10 + (b - '0');
			}else{
				return minus ? -num : num;
			}
			b = readByte();
		}
	}
	
	private static void tr(Object... o) { if(INPUT.length() != 0)System.out.println(Arrays.deepToString(o)); }
}


Measured memory_bytes: 37548