#include<bits/stdc++.h>
#define N 810
#define p_b push_back
#define m_p make_pair
#define m1 first
#define m2 second
#define inf 1e9

using namespace std;

typedef pair<int,int> PII;
pair<PII,int> q[N*N];
bool vis[N][N];
const int tx[4]={1,0,-1,0},ty[4]={0,1,0,-1};
int l,r,n,m,k,ans=inf;
char mp[N][N];

int main(){
	int i,j,x,y,d;
	scanf("%d%d%d",&n,&m,&k);
	for(i=1;i<=n;i++){
		scanf("%s",mp[i]+1);
		for(j=1;j<=m;j++)
		if(mp[i][j]=='S') q[1]=m_p(m_p(i,j),0);
	}
	
	x=q[1].m1.m1; y=q[1].m1.m2;
	ans=min(ans,(n-1-x)/k+1);
	ans=min(ans,(x-2)/k+1);
	ans=min(ans,(m-1-y)/k+1);
	ans=min(ans,(y-2)/k+1);
	l=1; r=1;
	while(l<=r){
		if(q[l].m2==k) break;
		for(i=0;i<4;i++){
			x=q[l].m1.m1+tx[i]; y=q[l].m1.m2+ty[i]; d=q[l].m2+1;
			if(x<1||x>n||y<1||y>m||vis[x][y]||mp[x][y]=='#') continue;
			if(x==1||x==n||y==0||y==m){puts("1"); return 0;}
			vis[x][y]=1; q[++r]=m_p(m_p(x,y),d);
			ans=min(ans,(n-1-x)/k+1);
			ans=min(ans,(x-2)/k+1);
			ans=min(ans,(m-1-y)/k+1);
			ans=min(ans,(y-2)/k+1);
		}
		l++;
	}
	printf("%d\n",ans+1);
	return 0;
}