//#pragma GCC optimize("Os")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,fma,abm,mmx,avx,avx2,tune=native")
#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#ifdef rd
#define trace(...) cout<<"Line:"<<__LINE__<<" "; __f(#__VA_ARGS__, __VA_ARGS__)
template<typename Arg1>
void __f(const char* name, Arg1&& arg1) {
	cout<<name<<" : "<<arg1<<endl;
}
template<typename Arg1, typename ... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args) {
	const char* comma=strchr(names+1,',');
	cout.write(names,comma-names)<<" : "<<arg1<<" | ";
	__f(comma+1,args...);
}
#else
#define trace(...)
#define endl '\n'
#endif
#define pb push_back
#define fi first
#define se second
//#define int long long
typedef long long ll;
typedef float f80;
//#define double long double
#define pii pair<int,int>
#define pll pair<ll,ll>
#define sz(x) ((long long)x.size())
#define fr(a,b,c) for(int a=b; a<=c; a++)
#define rep(a,b,c) for(int a=b; a<c; a++)
#define trav(a,x) for(auto &a:x)
#define all(con) con.begin(),con.end()
const ll infl=0x3f3f3f3f3f3f3f3fLL;
const int infi=0x3f3f3f3f;
//const int mod=998244353;
int mod=1000000007;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef tree<int, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> oset;
auto clk=clock();
mt19937_64 rang(chrono::high_resolution_clock::now().time_since_epoch().count());
int rng(int lim) {
	uniform_int_distribution<int> uid(0,lim-1);
	return uid(rang);
}
int powm(ll a, ll b) {
	int res=1;
	while(b) {
		if(b&1)
			res=(res*a)%mod;
		a=(a*a)%mod;
		b>>=1;
	}
	return res;
}

char g[805][805];
int dist[805][805];
void solve() {
	int n,m,k;
	cin>>n>>m>>k;
	memset(g,'#',sizeof(g));
	memset(dist,infi,sizeof(dist));
	fr(i,1,n)
		fr(j,1,m)
			cin>>g[i][j];
	int ans=infi;
	pii st;
	fr(i,1,n)
		fr(j,1,m)
			if(g[i][j]=='S') {
				st.fi=i;
				st.se=j;
			}
	queue<pii> bfs;
	bfs.push(st);
	vector<int> dx={1,0,-1,0},dy={0,1,0,-1};
	dist[st.fi][st.se]=0;
	while(!bfs.empty()) {
		pii at=bfs.front();
		bfs.pop();
		for(int i=0; i<4; i++) {
			if(g[at.fi+dx[i]][at.se+dy[i]]=='.'&&dist[at.fi+dx[i]][at.se+dy[i]]>dist[at.fi][at.se]+1) {
				dist[at.fi+dx[i]][at.se+dy[i]]=dist[at.fi][at.se]+1;
				bfs.push({at.fi+dx[i],at.se+dy[i]});
			}
		}
	}
	fr(i,1,n) {
		fr(j,1,m) {
			if(dist[i][j]<=k) {
				ans=min(ans,1+(i+k-1)/k);
				ans=min(ans,1+(j+k-1)/k);
				ans=min(ans,1+(n-i+k-1)/k);
				ans=min(ans,1+(m-j+k-1)/k);
			}
		}
	}
	cout<<ans<<endl;
}
signed main() {
	ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	srand(chrono::high_resolution_clock::now().time_since_epoch().count());
	cout<<fixed<<setprecision(10);
	int t=1;
//	cin>>t;
	fr(i,1,t)
		solve();
#ifdef rd
	cout<<endl<<endl<<endl<<endl<<"Time elapsed: "<<(double)(clock()-clk)/CLOCKS_PER_SEC<<endl;
#endif
	return 0;
}
