#include <bits/stdc++.h>
#define int long long
#define ll long long
using ull = unsigned long long;
using namespace std;
#define dump(x)                             \
    if (dbg) {                              \
        cerr << #x << " = " << (x) << endl; \
    }
#define overload4(_1, _2, _3, _4, name, ...) name
#define FOR1(n) for (ll i = 0; i < (n); ++i)
#define FOR2(i, n) for (ll i = 0; i < (n); ++i)
#define FOR3(i, a, b) for (ll i = (a); i < (b); ++i)
#define FOR4(i, a, b, c) for (ll i = (a); i < (b); i += (c))
#define FOR(...) overload4(__VA_ARGS__, FOR4, FOR3, FOR2, FOR1)(__VA_ARGS__)
#define FORR(i, a, b) for (int i = (a); i <= (b); ++i)
#define bit(n, k) ((n >> k) & 1) /*nのk bit目*/
namespace mydef {
const int INF = 1ll << 60;
const int MOD = 1e9 + 7;
template <class T>
bool chmin(T& a, const T& b) {
    if (a > b) {
        a = b;
        return 1;
    } else
        return 0;
}
template <class T>
bool chmax(T& a, const T& b) {
    if (a < b) {
        a = b;
        return 1;
    } else
        return 0;
}
void Yes(bool flag = true) {
    if (flag)
        cout << "Yes" << endl;
    else
        cout << "No" << endl;
}
void No(bool flag = true) {
    Yes(!flag);
}
void YES(bool flag = true) {
    if (flag)
        cout << "YES" << endl;
    else
        cout << "NO" << endl;
}
void NO(bool flag = true) {
    YES(!flag);
}
template <typename A, size_t N, typename T>
void Fill(A (&array)[N], const T& val) {
    std::fill((T*)array, (T*)(array + N), val);
}
bool dbg = true;
}  // namespace mydef
using namespace mydef;
#define pb push_back
//#define mp make_pair
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define all(v) (v).begin(), (v).end()
#define SZ(x) ((int)(x).size())
#define vi vector<int>
#define vvi vector<vector<int>>
#define vp vector<pair<int, int>>
#define vvp vector<vector<pair<int, int>>>
#define pi pair<int, int>
//#define P pair<int, int>
//#define V vector<int>
//#define S set<int>
#define asn ans
const int dx[] = {1, 0, -1, 0, 1, 1, -1, -1, 0};
const int dy[] = {0, -1, 0, 1, 1, -1, 1, -1, 0};

int H, W, K;
string A[1010];
int Sx, Sy;
int d[1010][1010];

int f(int x, int y) {
    return min(min(x, H - 1 - x), min(y, W - 1 - y));
}

void solve() {
    Fill(d, -1);
    priority_queue<pair<int, pair<int, int>>> que;
    que.push(make_pair(K, make_pair(Sx, Sy)));
    while (!que.empty()) {
        auto p = que.top();
        que.pop();
        int now = p.first, x = p.second.first, y = p.second.second;
        if (now <= d[x][y])
            continue;
        d[x][y] = now;
        if (now == 0)
            continue;
        int nxt = now - 1;
        for (int i = 0; i < 4; i++) {
            int nx = x + dx[i], ny = y + dy[i];
            if (0 <= nx && nx < H && 0 <= ny && ny < W) {
                if (A[nx][ny] == '.' && d[nx][ny] < nxt) {
                    que.push(make_pair(nxt, make_pair(nx, ny)));
                }
            }
        }
    }
    int dist = INF;
    for (int i = 0; i < H; i++) {
        for (int j = 0; j < W; j++) {
            if (d[i][j] >= 0) {
                chmin(dist, f(i, j));
            }
            //cout << d[i][j] << " ";
        }
        //cout << endl;
    }
    cout << (dist + K - 1) / K + 1 << endl;
}

signed main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    cin >> H >> W >> K;
    for (int i = 0; i < H; i++) {
        cin >> A[i];
        for (int j = 0; j < W; j++) {
            if (A[i][j] == 'S') {
                Sx = i;
                Sy = j;
            }
        }
    }

    solve();
    return 0;
}


Measured memory_bytes: 12340