#include <bits/stdc++.h>
using namespace std;
const int INF=1e9,N=1000,dx[]={0,0,1,-1},dy[]={1,-1,0,0};
int n,m,k,x,y;
char c[N][N];
bool vis[N][N];
int main()
{
	//freopen("qc.in","r",stdin);
	scanf("%d%d%d",&n,&m,&k);
	for(int i=0;i<n;i++)
	{
		scanf("%s",&c[i]);
		for(int j=0;j<m;j++)if(c[i][j]=='S')x=i,y=j;
	}
	int ans=min(min(x,y),min(n-x-1,m-y-1));
	vis[x][y]=1;
	if(ans%k==0)ans=ans/k;
	else ans=ans/k+1;
	int minv=ans+1;
	queue<pair<int,pair<int,int> > >q;
	q.push(make_pair(0,make_pair(x,y)));
	while(!q.empty())
	{
		pair<int,pair<int,int> >t=q.front();
		q.pop();
		if(t.first>=k)continue;
		for(int w=0;w<4;w++)
		{
			int nx=t.second.first+dx[w],ny=t.second.second+dy[w];
			if(nx<0||nx>=n||ny<0||ny>=m)continue;
			if(vis[nx][ny])continue;
			if(c[nx][ny]=='#')continue;
			vis[nx][ny]=true;
			int res=min(min(nx,ny),min(n-nx-1,m-ny-1));
			if(res%k==0)res=res/k;
			else res=res/k+1;
			minv=min(minv,res+1);
			q.push(make_pair(t.first+1,make_pair(nx,ny)));
		}
	}
	printf("%d\n",minv);
	return 0;
}