#include <iostream>
#include <string>
#include <cmath>
#include<algorithm>
#include<stack>
#include<queue>
#include<map>
#include<set>
#include<iomanip>
#define _USE_MATH_DEFINES
#include <math.h>
#include <functional>
using namespace std;

#define rep(i,x) for(ll i=0;i<x;i++)
#define repn(i,x) for(ll i=1;i<=x;i++)

typedef long long ll;
const ll INF = 1e17;
const ll MOD = 1000000007;
const ll MAX = 4000001;

ll max(ll a, ll b) {
	if (a > b) { return a; }
	return b;
}

ll min(ll a, ll b) {
	if (a > b) { return b; }
	return a;
}

ll gcd(ll a, ll b) {
	if (b == 0) { return a; }
	if (a < b) { return gcd(b, a); }
	return gcd(b, a % b);
}

ll lcm(ll a, ll b) {
	return a / gcd(a, b) * b;
}

struct edge {
	ll ind;
	ll fr;
	ll to;
	ll d;
};

class mint {
    long long x;
public:
    mint(long long x = 0) : x((x% MOD + MOD) % MOD) {}
    mint operator-() const {
        return mint(-x);
    }
    mint& operator+=(const mint& a) {
        if ((x += a.x) >= MOD) x -= MOD;
        return *this;
    }
    mint& operator-=(const mint& a) {
        if ((x += MOD - a.x) >= MOD) x -= MOD;
        return *this;
    }
    mint& operator*=(const  mint& a) {
        (x *= a.x) %= MOD;
        return *this;
    }
    mint operator+(const mint& a) const {
        mint res(*this);
        return res += a;
    }
    mint operator-(const mint& a) const {
        mint res(*this);
        return res -= a;
    }
    mint operator*(const mint& a) const {
        mint res(*this);
        return res *= a;
    }

    mint operator^(const ll& t)const {
        if (!t) return 1;
        mint a = pow(t >> 1);
        a *= a;
        if (t & 1) a *= *this;
        return a;
    }

    mint pow(ll t) const {
        if (!t) return 1;
        mint a = pow(t >> 1);
        a *= a;
        if (t & 1) a *= *this;
        return a;
    }
    // for prime MOD
    mint inv() const {
        return pow(MOD - 2);
    }
    mint& operator/=(const mint& a) {
        return (*this) *= a.inv();
    }
    mint operator/(const mint& a) const {
        mint res(*this);
        return res /= a;
    }

    friend ostream& operator<<(ostream& os, const mint& m) {
        os << m.x;
        return os;
    }
};

//////////////////////////

int main() {
    
    ll H, W, K;
    cin >> H >> W >> K;

    vector<vector<char>> A(H + 1, vector<char>(W + 1));
    vector<vector<ll>> dis(H + 1, vector<ll>(W + 1,INF));
    queue<ll> qh;
    queue<ll> qw;

    repn(i, H)repn(j, W) {
        cin >> A[i][j];
        if (A[i][j] == 'S') {
            dis[i][j] = 0;
            qh.push(i);
            qw.push(j);
        }
    }

    while (!qh.empty()) {
        ll i = qh.front();
        qh.pop();
        ll j = qw.front();
        qw.pop();

        rep (k, 4) {
            ll x = i;
            ll y = j;

            if (k < 2) { x += -1 + 2 * (k % 2); }
            else { y += -1 + 2 * (k % 2); }

            if (x <= 0 || x > H || y <= 0 || y > W) { continue; }
            if (A[x][y] == '#') { continue; }
            if (dis[x][y] != INF) { continue; }
            dis[x][y] = dis[i][j] + 1;
            qh.push(x);
            qw.push(y);
        }

    }

    ll ans = INF;

    repn(i, H)repn(j, W) {
        //cout << i << j << dis[i][j] << endl;
        if (dis[i][j] > K) { continue; }
        ll x = min(i - 1, min(j - 1, min(H - i, W - j)));
        if (x > 0) { x = (x - 1) / K + 1; }
        ans = min(ans, x + 1);
    }

    cout << ans;

	system("PAUSE");
}

Measured memory_bytes: 6144