// Copyright (C) 2017 __debug.

// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; version 3

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program; If not, see <http://www.gnu.org/licenses/>.


#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/priority_queue.hpp>

#define x first
#define y second
#define MP std::make_pair
#define SZ(x) ((int)(x).size())
#define ALL(x) (x).begin(), (x).end()
#define DEBUG(...) fprintf(stderr, __VA_ARGS__)
#ifdef __linux__
#define getchar getchar_unlocked
#define putchar putchar_unlocked
#endif

using std::pair;
using std::vector;
using std::string;

typedef long long LL;
typedef pair<int, int> Pii;

const int oo = 0x3f3f3f3f;

template<typename T> inline bool chkmax(T &a, T b) { return a < b ? a = b, true : false; }
template<typename T> inline bool chkmin(T &a, T b) { return b < a ? a = b, true : false; }
string procStatus()
{
    std::ifstream t("/proc/self/status");
    return string(std::istreambuf_iterator<char>(t), std::istreambuf_iterator<char>());
}
template<typename T> T read(T &x)
{
    int f = 1;
    char ch = getchar();
    for (; !isdigit(ch); ch = getchar())
        f = (ch == '-' ? -1 : 1);
    for (x = 0; isdigit(ch); ch = getchar())
        x = 10 * x + ch - '0';
    return x *= f;
}
template<typename T> void write(T x)
{
    if (x == 0) {
        putchar('0');
        return;
    }
    if (x < 0) {
        putchar('-');
        x = -x;
    }
    static char s[20];
    int top = 0;
    for (; x; x /= 10)
        s[++top] = x % 10 + '0';
    while (top)
        putchar(s[top--]);
}
// EOT

const int MAXN = 805;

int N, M, K;
char A[MAXN][MAXN];

void input()
{
    read(N); read(M); read(K);
    for (int i = 1; i <= N; ++i) {
        scanf("%s", A[i] + 1);
    }
}

const int DX[4] = {-1, 0, 0, +1};
const int DY[4] = {0, -1, +1, 0};

void solve()
{
    Pii s;
    for (int i = 1; i <= N; ++i) {
        for (int j = 1; j <= M; ++j) {
            if (A[i][j] == 'S') {
                s = MP(i, j);
                break;
            }
        }
    }

    static int dis[MAXN][MAXN];
    static Pii q[MAXN * MAXN];
    int front = 0, rear = 0;

    memset(dis, +oo, sizeof(dis));
    dis[s.x][s.y] = 0;
    q[rear++] = s;
    while (front != rear) {
        Pii u = q[front++];
        if (u.x == 1 || u.x == N || u.y == 1 || u.y == M) {
            puts("1");
            return;
        }
        if (dis[u.x][u.y] == K)
            break;
        for (int i = 0; i < 4; ++i) {
            Pii v(u.x + DX[i], u.y + DY[i]);
            if (A[v.x][v.y] != '#' && chkmin(dis[v.x][v.y], dis[u.x][u.y] + 1))
                q[rear++] = v;
        }
    }

    int min = +oo;
    for (int i = 0; i < rear; ++i) {
        Pii u = q[i];
        chkmin(min, std::min(std::min(u.x - 1, N - u.x), std::min(u.y - 1, M - u.y)));
    }
    int ans = 1 + min / K + !!(min % K);

    printf("%d\n", ans);
}

int main()
{
#ifdef __DEBUG
    freopen("C.in", "r", stdin);
    freopen("C.out", "w", stdout);
#endif

    input();
    solve();

    return 0;
}

// 五月天山雪，无花只有寒。
//     -- 李白《塞下曲六首·其一》


Measured memory_bytes: 5504