#include <bits/stdc++.h>
const long long INF = 1LL << 60;
const long long MOD = 1000000007;
const double PI = acos(-1.0);
#define rep(i, n) for (ll i = 0; i < (n); ++i)
#define rep1(i, n) for (ll i = 1; i <= (n); ++i)
#define rrep(i, n) for (ll i = (n - 1); i >= 0; --i)
#define perm(c) sort(ALL(c));for(bool c##p=1;c##p;c##p=next_permutation(ALL(c)))
#define ALL(obj) (obj).begin(), (obj).end()
#define RALL(obj) (obj).rbegin(), (obj).rend()
#define pb push_back
#define to_s to_string
#define len(v) (ll)v.size()
#define UNIQUE(v) v.erase(unique(v.begin(), v.end()), v.end())
#define print(x) cout << (x) << '\n'
#define drop(x) cout << (x) << '\n', exit(0)
#define debug(x) cout << #x << ": " << (x) << '\n'
using namespace std;
using ll = long long;
typedef pair<ll, ll> P;
typedef vector<ll> vec;
typedef vector<vector<ll>> vec2;
typedef vector<vector<vector<ll>>> vec3;
template<class S, class T> inline bool chmax(S &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class S, class T> inline bool chmin(S &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
inline ll msb(ll v) { return 1 << (31 - __builtin_clzll(v)); }
inline ll devc(ll x, ll y) { return (x + y - 1) / y; }
inline ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
inline ll lcm(ll a, ll b) { return a * (b / gcd(a, b)); }

struct IoSetup {
    IoSetup() {
        cin.tie(nullptr);
        ios::sync_with_stdio(false);
        cout << fixed << setprecision(10);
        cerr << fixed << setprecision(10);
    }
} iosetup;

template< typename T1, typename T2 >
ostream &operator << (ostream &os, const pair< T1, T2 > &p) {
    os << p.first << " " << p.second;
    return os;
}

template< typename T1, typename T2 >
istream &operator >> (istream &is, pair< T1, T2 > &p) {
    is >> p.first >> p.second;
    return is;
}

template< typename T1, typename T2, typename T3 >
ostream &operator << (ostream &os, const tuple< T1, T2, T3 > &t) {
    os << get<0>(t) << " " << get<1>(t) << " " << get<2>(t);
    return os;
}

template< typename T1, typename T2, typename T3 >
istream &operator >> (istream &is, tuple< T1, T2, T3 > &t) {
    is >> get<0>(t) >> get<1>(t) >> get<2>(t);
    return is;
}

template< typename T >
ostream &operator << (ostream &os, const vector< T > &v){
    for (int i = 0; i < (int)v.size(); ++i) {
        os << v[i] << (i + 1 != v.size() ? " " : "");
    }
    return os;
}

template< typename T >
istream &operator >>  (istream &is, vector< T > &v){
    for(T &in : v) is >> in;
    return is;
}

/*---------------------------------    Tools    ------------------------------------------*/
template< typename T >
vector<T> cumsum(const vector<T> &X){
    vector<T> res(X.size() + 1, 0);
    for(int i = 0; i < X.size(); ++i) res[i + 1] += res[i] + X[i];
    return res;
}

template< typename S, typename T, typename F>
pair<T, T> bisearch(S left, T right, F f) {
    while(abs(right - left) > 1){
        T mid = (right + left) / 2;
        if(f(mid)) right = mid;
        else left = mid;
    }
    return {left, right};
}

template< typename S, typename T, typename F>
double trisearch(S left, T right, F f, int maxLoop = 90){
    double low = left, high = right;
    while(maxLoop--){
        double mid_left = high / 3 + low * 2 / 3;
        double mid_right = high * 2 / 3 + low / 3;
        if(f(mid_left) >= f(mid_right)) low = mid_left;
        else high = mid_right;
    }
    return (low + high) * 0.5;
}

/*---------------------------------Grid Template------------------------------------------*/
vector<string> getGrid(int H, int W){
    vector<string> grid;
    string s;
    for (int i = 0; i < H; ++i){
        cin >> s;
        grid.pb(s);
    }
    return grid;
}

/*------------------------------- Main Code Here -----------------------------------------*/

int main()
{
    ll H, W, K;
    cin >> H >> W >> K;
    vector<string> grid = getGrid(H, W);
    P start;
    rep(i, H) rep(j, W) if (grid[i][j] == 'S') start = {i, j};

    queue<pair<P, int>> que;
    que.push({start, 0});

    ll dx[4] = {1, 0, -1, 0};
    ll dy[4] = {0, 1, 0, -1};
    ll nowx = start.first, nowy = start.second;

    ll ans = min({devc(nowx, K), devc(nowy, K), devc(H - 1 - nowx, K), devc(W - 1 - nowy, K)}) + 1;

    vec2 visited(H, vec(W, 0));

    while(!que.empty()){
        pair<P, int> now = que.front();
        ll nx = now.first.first, ny = now.first.second;
        ll move = now.second;

        que.pop();
        visited[nx][ny] = 1;

        ll magic = min({devc(nx, K), devc(ny, K), devc(H - 1 - nx, K), devc(W - 1 - ny, K)}) + 1;
        chmin(ans, magic);

        if(move >= K) break;

        rep(i, 4){
            P next = {now.first.first + dx[i], now.first.second + dy[i]};
            ll x = next.first, y = next.second;
            if(grid[x][y] == '#') continue;
            if(visited[x][y]) continue;
            if(x <= 0 or y <= 0 or x >= H - 1 or y >= W - 1) drop(1);
            if(now.second + 1 > K) continue;

            visited[x][y] = 1;
            que.push({next, now.second + 1});
        }
    }

    print(ans);

    return 0;
}

Measured memory_bytes: 6016