#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <queue>
#include <stdio.h>
#include <string.h>
#include <math.h>
using namespace std;

char a[802][808];

int main() {
    int h, w, k;
    cin >> h >> w >> k;

    int i0, j0;
    for (int i = 1; i <= h; i++) {
        cin >> a[i];
        for (int j = 0; j < w; j++) {
            if (a[i][j] == 'S') i0 = i, j0 = j, a[i][j] = '.';
        }
    }

    queue<pair<int, int>> q;
    q.push({ i0, j0 });
    int d = 800;

    for (int l = 0; l <= k; l++) {
        int n = (int)q.size();
        for (int m = 0; m < n; m++) {
            auto p = q.front(); q.pop();
            int i = p.first, j = p.second;
            if (a[i][j] != '.') continue;
            a[i][j] = '+';
            d = min(d, i - 1);
            d = min(d, h - i);
            d = min(d, j);
            d = min(d, w - 1 - j);
            q.push({ i - 1, j });
            q.push({ i, j - 1 });
            q.push({ i, j + 1 });
            q.push({ i + 1, j });
        }
    }

    cout << (d + k - 1) / k + 1 << endl;

    return 0;
}