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

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef double ld;
//#define ll __int128
//#define int ll
//#define int ll
//#define char ll
#define double ld
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 MAX_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 MAX_HOME
    freopen("input.txt", "r", stdin);
    clock_t start = clock();
#endif
    cout << setprecision(12) << fixed;
    smain();
#ifdef MAX_HOME
    cout << "\n\nTOTAL EXECUTION TIME: " << float(clock() - start) / CLOCKS_PER_SEC << endl;
#endif
    return 0;
}

const int N = 888;
int n, m;
string mat[N];
int dist[N][N];

vi di = {0, 0, -1, 1};
vi dj = {-1, 1, 0, 0};

const int oo = 1e9 + 10;

void smain() {
    fori (i, N) {
        fori (j, N) {
            dist[i][j] = -1;
        }
    }
    cin >> n >> m;
    int k;
    cin >> k;
    fori (i, n) {
        cin >> mat[i];
    }
    pii st;
    fori (i, n) {
        fori (j, m) {
            if (mat[i][j] == 'S') {
                st = {i, j};
                if (i == 0 || i + 1 == n || j == 0 || j + 1 == m) {
                    cout << "0";
                    return;
                }
            }
        }
    }

    queue<pii> q;

    q.push(st);

    dist[st.first][st.second] = 0;

    while (!q.empty()) {
        pii v = q.front();
        q.pop();

        fori (dir, di.size()) {
            int i = v.first + di[dir];
            int j = v.second + dj[dir];
            if (i >= 0 && i < n && j >= 0 && j < m && mat[i][j] != '#' && dist[i][j] == -1) {
                dist[i][j] = dist[v.first][v.second] + 1;
                q.push({i, j});
            }
        }
    }
    int ans = oo;
    fori (i, n) {
        fori (j, m) {
            if (dist[i][j] != -1 && dist[i][j] <= k) {
                inmin(ans, 1 + (min(min(i, n - i - 1), min(j, m - j - 1)) + k - 1) / k);
            }
        }
    }
    cout << ans;

}

Measured memory_bytes: 4096