#include <stdio.h>
#include <string.h>
#include <queue>
#include <algorithm>
using namespace std;
char mp[801][802];
int dist[801][801];
int main()
{
	int n,m,k;
	scanf("%d%d%d%*c",&n,&m,&k);
	int sx,sy;
	for (int i=1;i<=n;++i)
	{
		scanf("%s",mp[i]+1);
		for (int j=1;j<=m;++j)
		{
			if (mp[i][j]=='S')
			{
				sx=i;
				sy=j;
			}
		}
	}
	queue<pair<int,int> > q;
	q.push(make_pair(sx,sy));
	memset(dist,-1,sizeof(dist));
	dist[sx][sy]=0;
	while (!q.empty())
	{
		int fx=q.front().first,fy=q.front().second;
		q.pop();
		if (dist[fx][fy]==k)
			continue;
		for (int i=-1;i<=1;++i)
			for (int j=-1;j<=1;++j)
			{
				int ox=fx+i,oy=fy+j;
				if (ox>0&&ox<=n&&oy>0&&oy<=m&&(i==0||j==0)&&mp[ox][oy]!='#'&&dist[ox][oy]==-1)
				{
					dist[ox][oy]=dist[fx][fy]+1;
					q.push(make_pair(ox,oy));
				}
			}
	}
	int mindist=1000000000;
	for (int i=1;i<=n;++i)
		for (int j=1;j<=m;++j)
			if (dist[i][j]!=-1)
			{
				int curdist=min(i-1,min(n-i,min(j-1,m-j)));
				if (curdist<mindist)
					mindist=curdist;
			}
	printf("%d",1+(mindist%k?mindist/k+1:mindist/k));
	return 0;
}
