#include <bits/stdc++.h>
#define INF 1000000009
using namespace std;

int n,m,k,x,y;
char c[1000][1000];
bool vis[1000][1000];
int dx[4]={0,0,1,-1};
int dy[4]={1,-1,0,0};

int main()
{
	cin>>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]=true;
    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||ny<0||nx>=n||ny>=m) continue;
			if(c[nx][ny]=='#') continue;
			if(vis[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)));
		}
	}
	cout<<minv<<endl;
	return 0;
}
/*
7 7 1
######.
#####..
####..#
###S.##
##..###
#..####
..#####

HAHA!
*/