#include<iostream>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cmath>
#include<algorithm>
#include<queue>
using namespace std;

const int N=1005;

struct node{
	int x,y;
	node(){}
	node(int x,int y):x(x),y(y){}
};
int n,m,d,sx,sy,x,y,ans;
int dx[4]={0,1,-1,0},dy[4]={1,0,0,-1},dep[N][N];
bool vis[N][N];
char s[N][N];
queue<node> q;

int main(){
	int i,j; node k;
	scanf("%d%d%d",&n,&m,&d);
	for (i=1;i<=n;i++){
		scanf("%s",s[i]+1);
		for (j=1;j<=m;j++) if (s[i][j]=='S') sx=i,sy=j;
	}
	q.push(node(sx,sy)); ans=n+m;
	vis[sx][sy]=1;
	while (!q.empty()){
		k=q.front(); q.pop();
		x=k.x; y=k.y;
		ans=min(ans,min(min(x-1,n-x),min(y-1,m-y)));
		if (dep[x][y]==d) continue;
		for (i=0;i<4;i++){
			x=k.x+dx[i]; y=k.y+dy[i];
			if (x<1||x>n||y<1||y>m) continue;
			if (vis[x][y]||s[x][y]!='.') continue;
			dep[x][y]=dep[k.x][k.y]+1;
			vis[x][y]=1;
			q.push(node(x,y));
		}
	}
	printf("%d\n",(ans+d-1)/d+1);
	return 0;
} 