#pragma GCC optimize("O3")
#include<bits/stdc++.h>
#define rc(x) return cout<<x<<endl,0
#define pb push_back
#define in insert
#define er erase
#define fr first
#define sc second
typedef long long ll;
const long long llinf=LLONG_MAX;
const int inf=INT_MAX;
const int nmax=1e5+5;
const int mod=1e9+7;
using namespace std;
int n,m,k,i,j,l,r,viz[801][801],ans=1e8;
pair<int,int>a[]={{1,0},{-1,0},{0,1},{0,-1}};
char c[801][801];
void solve(int i,int j)
{
	viz[i][j]=1;
	int d=min(min(i,j),min(n-i-1,m-j-1));
	ans=min(ans,(d+k-1)/k);
	for(int t=0;t<4;t++)if(i+a[t].fr>=0 && i+a[t].fr<n && j+a[t].sc>=0 && j+a[t].sc<m && !viz[i+a[t].fr][j+a[t].sc] && c[i+a[t].fr][j+a[t].sc]!='#' && abs(l-i-a[t].fr)+abs(r-j-a[t].sc)<=k)solve(i+a[t].fr,j+a[t].sc);
}
int main()
{
	//freopen("sol.in","r",stdin);
	ios_base::sync_with_stdio(false);cin.tie(0);cerr.tie(0);cout.tie(0);
	cin>>n>>m>>k;
	for(i=0;i<n;i++)
	 for(j=0;j<m;j++)
	 {
	 	cin>>c[i][j];
	 	if(c[i][j]=='S')l=i,r=j;
	 }
	solve(l,r);
	cout<<ans+1<<endl;
	return 0;
}