#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <utility>
#include <tuple>
#include <cstdint>
#include <cstdio>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <deque>
#include <unordered_map>
#include <unordered_set>
#include <bitset>
#include <cctype>
#include <functional>
#include <ctime>
#include <cmath>
#include <limits>
#include <numeric>
#include <type_traits>
#include <iomanip>
#include <float.h>
#include <math.h>
using namespace std;
using ll = long long;
unsigned euclidean_gcd(unsigned a, unsigned b) {
    if (a < b) return euclidean_gcd(b, a);
    unsigned r;
    while ((r = a % b)) {
        a = b;
        b = r;
    }
    return b;
}

ll ll_gcd(ll a, ll b) {
    if (a < b) return ll_gcd(b, a);
    ll r;
    while ((r = a % b)) {
        a = b;
        b = r;
    }
    return b;
}

class UnionFind {
public:
    vector <ll> par;
    vector <ll> siz;
    UnionFind(ll sz_) : par(sz_), siz(sz_, 1LL) {
        for (ll i = 0; i < sz_; ++i) par[i] = i;
    }
    void init(ll sz_) {
        par.resize(sz_);
        siz.assign(sz_, 1LL);
        for (ll i = 0; i < sz_; ++i) par[i] = i;
    }
    ll root(ll x) {
        while (par[x] != x) {
            x = par[x] = par[par[x]];
        }
        return x;
    }
    bool merge(ll x, ll y) {
        x = root(x);
        y = root(y);
        if (x == y) return false;
        if (siz[x] < siz[y]) swap(x, y);
        siz[x] += siz[y];
        par[y] = x;
        return true;
    }

    bool issame(ll x, ll y) {
        return root(x) == root(y);
    }

    ll size(ll x) {
        return siz[root(x)];
    }
};

long long modpow(long long a, long long n, long long mod) {
    long long res = 1;
    while (n > 0) {
        if (n & 1) res = res * a % mod;
        a = a * a % mod;
        n >>= 1;
    }
    return res;
}

long long modinv(long long a, long long mod) {
    return modpow(a, mod - 2, mod);
}

void dfs(vector<string> &maze,ll nowi,ll nowj,ll &ans,ll &h,ll &w,vector<vector<ll>> &seen,ll kyori,ll k) {
    ans = min(ans, min(min(nowi, h - nowi - 1), min(nowj, w - nowj - 1)));
    seen[nowi][nowj] = kyori;
    if (kyori == k||ans==0)return;
    if ((!(nowi + 1 >= h)) && maze[nowi + 1][nowj] == '.' && seen[nowi + 1][nowj] > kyori+1)dfs(maze, nowi + 1, nowj, ans, h, w, seen, kyori + 1, k);
    if ((!(nowj + 1 >= w)) && maze[nowi][nowj + 1] == '.' && seen[nowi][nowj + 1] > kyori+1)dfs(maze, nowi, nowj + 1, ans, h, w, seen, kyori + 1, k);
    if ((!(nowi - 1 < 0)) && maze[nowi - 1][nowj] == '.' && seen[nowi - 1][nowj] > kyori+1)dfs(maze, nowi - 1, nowj, ans, h, w, seen, kyori + 1, k);
    if ((!(nowj - 1 < 0)) && maze[nowi][nowj - 1] == '.' && seen[nowi][nowj - 1] > kyori+1)dfs(maze, nowi, nowj - 1, ans, h, w, seen, kyori + 1, k);
    return;
}

int main() {
    ll h, w, k;
    cin >> h >> w >> k;
    vector<string> z(h);
    for (int i = 0; i < h; i++) {
        cin >> z[i];
    }
    ll sih = 0;
    ll sjw = 0;
    for (int i = 0; i < h; i++) {
        for (int j = 0; j < w; j++) {
            if (z[i][j] == 'S') {
                sih = i;
                sjw = j;
            }
        }
    }
    vector<vector<ll>> zz(h, vector<ll>(w, 234567819));
    ll ans = 13413434127912;
    dfs(z, sih, sjw, ans, h, w, zz, 0, k);
    cout << (ans+k-1) / k+1 << endl;
}

Measured memory_bytes: 9072