#include <bits/stdc++.h>
using namespace std;
const int dx[] = {1, 0, -1, 0};
const int dy[] = {0, 1, 0, -1};
int n, m, k;
int d[1050][1050];
int sx, sy, x, y;
int xx, yy;
char c[1050][1050];
queue<pair<int, int> > q;
bool check(int a, int b) {
  if (a >= 0 && a < n && b >= 0 && b < m && c[a][b] != '#') {
    return true;
  }
  return false;
}
int minidis(int a, int b) {
  int cnt = a;
  cnt = min(min(b, n - 1 - a), m - 1 - b);
  return cnt;
}
void bfs() {
  while (!q.empty()) {
    x = q.front().first;
    y = q.front().second;
    q.pop();
    for (int i = 0; i < 4; i++) {
      xx = x + dx[i];
      yy = y + dy[i];
      if (check(xx, yy) && d[xx][yy] < 0) {
        d[xx][yy] = d[x][y] + 1;
        q.push(make_pair(xx, yy));
      }
    }
  }
}
int main() {
  cin >> n >> m >> k;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      cin >> c[i][j];
      if (c[i][j] == 'S') {
        sx = i;
        sy = j;
      }
    }
  }
  memset(d, -1, sizeof(d));
  d[sx][sy] = 0;
  q.push(make_pair(sx, sy));
  bfs();
  int res = 999999;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      if (d[i][j] >= 0 && d[i][j] <= k) {
        res = min(res, 1 + ((minidis(i, j) + k - 1) / k));
      }
    }
  }
  cout << res << endl;
  return 0;
}
