#include<bits/stdc++.h>
#include<queue>
using namespace std;
const int dx[]={1,0,-1,0};//position prepare
const int dy[]={0,1,0,-1};//position prepare
int n,m,k;
int d[1050][1050];//record distance
int sx,sy,x,y;
int xx,yy;
char c[1050][1050];
queue<pair<int,int> > q;
bool check(int a,int b){//check if the grid is in use
	if(a>=0&&a<n&&b>=0&&b<m&&c[a][b]!='#'){
		return true;
	}
	return false;
}
int minidis(int a,int b){
	int cnt=a;
	cnt=min(min(b,n-1-a),m-1-b);
	return cnt;
}
/*void bfs(){//bfs
	while(!q.empty()){
		x=q.front().first;
		y=q.front().second;
		q.pop();
		for(int i=0;i<4;i++){//check distance
			xx=x+dx[i];
			yy=y+dy[i];
			if(check(xx,yy)&&d[xx][yy]<0){
				d[xx][yy]=d[x][y]+1;
				q.push(make_pair(xx,yy));
			}
		}
	}
}
*/
int main(){
	cin>>n>>m>>k;
	for(int i=0;i<n;i++){
		for(int j=0;j<m;j++){
			cin>>c[i][j];
			if(c[i][j]=='S'){
				sx=i;
				sy=j;
			}
		}
	}
	memset(d,-1,sizeof(d));
	d[sx][sy]=0;
	q.push(make_pair(sx,sy));
	while(!q.empty()){
		x=q.front().first;
		y=q.front().second;
		q.pop();
		for(int i=0;i<4;i++){//check distance
			xx=x+dx[i];
			yy=y+dy[i];
			if(check(xx,yy)&&d[xx][yy]<0){
				d[xx][yy]=d[x][y]+1;
				q.push(make_pair(xx,yy));
			}
		}
	}
	long long res=999999999;
	for(int i=0;i<n;i++){
		for(int j=0;j<m;j++){
			if(d[i][j]>=0&&d[i][j]<=k){
				res=min(res,1+((minidis(i,j)+k-1)/k));
			}
		}
	}
	cout<<res<<endl;
	return 0;
}