#include <bits/stdc++.h>
#include <random>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef double ld;
//#define int ll
typedef vector<char> vc;
typedef vector<vc> vvc;
typedef vector<vvc> vvvc;
typedef pair<int, int> pii;
typedef pair<pii, pii> piii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<pii> vpi;
typedef vector< vi > vvi;
typedef vector< vvi > vvvi;
typedef vector<short> vs;
typedef vector<vs> vvs;
typedef vector<vvs> vvvs;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<ld> vld;
typedef vector<vld> vvld;
typedef vector<vvld> vvvld;
typedef vector<string> vst;
typedef vector<vst> vvst;
typedef pair<ld, ld> pld;

#define inmin(a, b) a = min(a, (b))
#define inmax(a, b) a = max(a, (b))
#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()
#define sqr(x) ((x) * (x))
#define fori(i, n) for(int i = 0; i < int(n); ++i)
#define SZ(a) ((int)((a).size()))
#define triple(T) tuple<T, T, T>
#define quad(T) tuple<T, T, T, T>
#define watch(x) cerr << (#x) << " = " << (x) << endl;

#ifdef RUS_HOME
#define cerr cout
#else
#define cerr if (false) cerr
#endif

const double PI = 2 * acos(0.0);
#define rand shittttty_shit
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng_64(chrono::steady_clock::now().time_since_epoch().count());

const string DIGITS = "0123456789";
const string ALPH = "abcdefghijklmnopqrstuvwxyz";


template <class T0, class T1>
inline ostream & operator << (ostream &out, pair<T0, T1> &a) {
    return out << "{" << a.first << ", " << a.second << "}";
}

template <class T0, class T1>
inline istream & operator >> (istream &in, pair<T0, T1> &a) {
    return in >> a.first >> a.second;
}

template <class T0, class T1, class T2>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << "}";
}

template <class T0, class T1, class T2, class T3>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2, T3> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << ", " <<  get<3>(a) << "}";
}

template<class T>
inline ostream & operator << (ostream &out, vector<T> &a) {
    out << "[";
    fori (i, a.size())
        out << a[i] << vector<string>{", ", "]  "}[i + 1 == a.size()];
    return out;
}


void smain();



signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
#ifdef RUS_HOME
    freopen("input", "r", stdin);
    clock_t start = clock();
#endif
    cout << setprecision(12) << fixed;
    smain();
#ifdef RUS_HOME
    cout << "\n\n\n\nTOTAL EXECUTION TIME: " << float( clock () - start ) /  CLOCKS_PER_SEC << endl;
#endif
    return 0;
}

const int N=800*800+100;

int n,m;
vector<string>s;
vi dx={0,0,1,-1},dy={1,-1,0,0};

bool correct(int i, int j){
    return(i>=0&&i<n&&j>=0&&j<m);
}

int qi[N],qj[N];



void smain() {

    int k;
    cin>>n>>m>>k;
    s.resize(n);
    int sti,stj;
    for(int i=0;i<n;i++){
        cin>>s[i];
        for(int j=0;j<m;j++){
            if(s[i][j]=='S'){
                sti=i;
                stj=j;
            }
        }
    }

    int st=0, fn=0;
    qi[fn]=sti;
    qj[fn]=stj;
    fn++;
    vvi used(n,vi(m)),b(n,vi(m,-1)),c(n,vi(m));
    used[sti][stj]=1;
    b[sti][stj]=0;
    while(st!=fn){
        int x=qi[st],y=qj[st];
        st++;
        for(int i=0;i<4;i++){
            int nx=x+dx[i],ny=y+dy[i];
            if(correct(nx,ny)&&!used[nx][ny]&&s[nx][ny]!='#'&&b[x][y]<k){
                used[nx][ny]=1;
                b[nx][ny]=b[x][y]+1;
                qi[fn]=nx;
                qj[fn]=ny;
                fn++;
            }
        }
    }
    int ans=800*800;
    for(int i=0;i<n;i++){
        for(int j=0;j<m;j++) {
            if (b[i][j] != -1) {
                inmin(ans,min({i,j,n-i-1,m-j-1}));
            }
        }
    }
    cout<<ans/k+(ans%k!=0)+1;


}

Measured memory_bytes: 13568