#include <bits/stdc++.h>
using namespace std;

// Define
using ll = long long;
using ull = unsigned long long;
using ld = long double;
template <class T> using pvector = vector<pair<T, T>>;
template <class T>
using rpriority_queue = priority_queue<T, vector<T>, greater<T>>;
constexpr const ll dx[4] = {1, 0, -1, 0};
constexpr const ll dy[4] = {0, 1, 0, -1};
constexpr const ll MOD = 1e9 + 7;
constexpr const ll mod = 998244353;
constexpr const ll INF = 1LL << 60;
constexpr const ll inf = 1 << 30;
constexpr const char rt = '\n';
constexpr const char sp = ' ';
#define len(x) ((ll) x.size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define mp make_pair
#define mt make_tuple
#define pb push_back
#define eb emplace_back
#define elif else if
#define fi first
#define se second

template <class T> bool chmax(T &a, const T &b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T> bool chmin(T &a, const T &b) {
    if (a > b) {
        a = b;
        return 1;
    }
    return 0;
}

// Debug
#define debug(...)                                                             \
    {                                                                          \
        cerr << __LINE__ << ": " << #__VA_ARGS__ << " = ";                     \
        for (auto &&X : {__VA_ARGS__}) cerr << "[" << X << "] ";               \
        cerr << rt;                                                            \
    }

#define dump(a, h, w)                                                          \
    {                                                                          \
        cerr << __LINE__ << ": " << #a << " = [" << rt;                        \
        rep(_i, h) {                                                           \
            rep(_j, w) {                                                       \
                if (abs(a[_i][_j]) >= INF / 2 and a[_i][_j] <= -INF / 2)       \
                    cerr << '-';                                               \
                if (abs(a[_i][_j]) >= INF / 2)                                 \
                    cerr << "∞" << sp;                                         \
                else                                                           \
                    cerr << a[_i][_j] << sp;                                   \
            }                                                                  \
            cerr << rt;                                                        \
        }                                                                      \
        cerr << "]" << rt;                                                     \
    }

#define vdump(a, n)                                                            \
    {                                                                          \
        cerr << __LINE__ << ": " << #a << " = [";                              \
        rep(_i, n) {                                                           \
            if (_i) cerr << sp;                                                \
            if (abs(a[_i]) >= INF / 2 and a[_i] <= -INF / 2) cerr << '-';      \
            if (abs(a[_i]) >= INF / 2)                                         \
                cerr << "∞" << sp;                                             \
            else                                                               \
                cerr << a[_i];                                                 \
        }                                                                      \
        cerr << "]" << rt;                                                     \
    }

// Loop
#define inc(i, a, n) for (ll i = (a), _##i = (n); i <= _##i; ++i)
#define dec(i, a, n) for (ll i = (a), _##i = (n); i >= _##i; --i)
#define rep(i, n) for (ll i = 0, _##i = (n); i < _##i; ++i)
#define each(i, a) for (auto &&i : a)

// Stream
#define fout(n) cout << fixed << setprecision(n)
struct io {
    io() { cin.tie(nullptr), ios::sync_with_stdio(false); }
} io;

// Speed
#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

// Math
inline constexpr ll gcd(const ll a, const ll b) {
    return b ? gcd(b, a % b) : a;
}
inline constexpr ll lcm(const ll a, const ll b) { return a / gcd(a, b) * b; }

inline constexpr ll modulo(const ll n, const ll m = MOD) {
    ll k = n % m;
    return k + m * (k < 0);
}
inline constexpr ll chmod(ll &n, const ll m = MOD) {
    n %= m;
    return n += m * (n < 0);
}
inline constexpr ll mpow(ll a, ll n, const ll m = MOD) {
    ll r = 1;
    rep(i, 64) {
        if (n & (1LL << i)) r *= a;
        chmod(r, m);
        a *= a;
        chmod(a, m);
    }
    return r;
}
inline ll inv(const ll n, const ll m = MOD) {
    ll a = n, b = m, x = 1, y = 0;
    while (b) {
        ll t = a / b;
        a -= t * b;
        swap(a, b);
        x -= t * y;
        swap(x, y);
    }
    return modulo(x, m);
}

struct Graph_2D {
    using P = pair<ll, ll>;
#define x first
#define y second
    ll H, W;
    vector<string> S;
    vector<vector<ll>> dist;
    vector<vector<P>> from;
    Graph_2D(ll H, ll W, vector<string> S)
        : H(H), W(W), S(S), dist(H, vector<ll>(W)), from(H, vector<P>(W)) {}
    void bfs(vector<P> start) {
        queue<P> Q;
        rep(i, H) rep(j, W) dist[i][j] = INF;
        each(i, start) Q.push(i), dist[i.x][i.y] = 0;
        while (!Q.empty()) {
            P now = Q.front();
            Q.pop();
            rep(i, 4) {
                P next = make_pair(clamp(now.x + dx[i], 0LL, H - 1),
                                   clamp(now.y + dy[i], 0LL, W - 1));
                if (S[next.x][next.y] != '#' and
                    dist[next.x][next.y] > dist[now.x][now.y] + 1) {
                    Q.push(next);
                    dist[next.x][next.y] = dist[now.x][now.y] + 1;
                    from[next.x][next.y] = now;
                }
            }
        }
    }
};

signed main() {
    ll H, W, K;
    cin >> H >> W >> K;
    vector<string> S(H);
    rep(i, H) cin >> S[i];

    Graph_2D G(H, W, S);
    vector<pair<ll, ll>> start;
    rep(i, H) rep(j, W) if (S[i][j] == 'S') start.pb({i, j});
    G.bfs(start);

    rep(i, H) rep(j, W) if (G.dist[i][j] <= K) start.pb({i, j});
    rep(i, H) rep(j, W) G.S[i][j] = '.';
    G.bfs(start);

    
    ll mn = INF;
    rep(i, H) chmin(mn, min(G.dist[i][0], G.dist[i][W - 1]));
    rep(i, W) chmin(mn, min(G.dist[0][i], G.dist[H - 1][i]));
    cout << (mn + K - 1) / K + 1 << rt;
}


Measured memory_bytes: 49452