#include<bits/stdc++.h>
using namespace std;
int n,m,k;
char grid[1000][1000];
int steps[1000][1000];
queue<pair<int,int> > q;
int dx[4]={0,1,0,-1};
int dy[4]={1,0,-1,0};
int main(){
	cin>>n>>m>>k;
	pair<int,int> stt;
	memset(steps,0x3f,sizeof(steps));
	for(int i=0;i<n;i++){
		scanf("%s",grid[i]);
		for(int j=0;j<m;j++){
			if(grid[i][j]=='S'){
				stt=make_pair(i,j);
			}
		}
	}
	steps[stt.first][stt.second]=0;
	q.push(stt);
	while(!q.empty()){
		stt=q.front();
		q.pop();
		if(steps[stt.first][stt.second]>=k)
			continue;
		for(int i=0;i<4;i++){
			int nx=stt.first+dx[i];
			int ny=stt.second+dy[i];
			if(nx>=0&&nx<n&&ny>=0&&ny<m){
				if(steps[nx][ny]>=1e9&&grid[nx][ny]!='#')
				{
					q.push(make_pair(nx,ny));
					steps[nx][ny]=steps[stt.first][stt.second]+1;
				}
			}
		}
	}
	int res=1e9;
	for(int i=0;i<n;i++){
		for(int j=0;j<m;j++){
			if(steps[i][j]<=k){
				int xx=min(min(i,j),min(n-i-1,m-j-1));
				res=min(res,(xx+k-1)/k+1);
			}
		}
	}
	cout<<res<<endl;
	return 0;
}
