#include <bits/stdc++.h>
using namespace std;
int H, W, K, dir[4][2] = {{0, 1}, {0, -1}, {1, 0}, {1, 1}};
char g[805][805];
bool vis[805][805];
queue<pair<int, pair<int, int> > > Q;
int d(int x) { return x / K + (x % K != 0); }
int main() {
  scanf("%d%d%d", &H, &W, &K);
  for (int i = 0; i < H; i++) scanf("%s", &g[i]);
  int sx, sy;
  for (int i = 0; i < H; i++) {
    for (int j = 0; j < W; j++) {
      if (g[i][j] == 'S') {
        sx = i;
        sy = j;
      }
    }
  }
  Q.push(make_pair(0, make_pair(sx, sy)));
  vis[sx][sy] = 1;
  int ans = 1000000000;
  while (!Q.empty()) {
    int dis = Q.front().first, x = Q.front().second.first,
        y = Q.front().second.second;
    Q.pop();
    for (int i = 0; i < 4; i++) {
      int newx = x + dir[i][0], newy = y + dir[i][1];
      if (newx < 0 || newx >= H || newy < 0 || newy >= W) continue;
      int newdis = dis + 1;
      if (newdis > K) continue;
      if (g[newx][newy] == '#') continue;
      if (vis[newx][newy])
        continue;
      else
        vis[newx][newy] = 1;
      Q.push(make_pair(newdis, make_pair(newx, newy)));
    }
  }
  for (int i = 0; i < H; i++)
    for (int j = 0; j < W; j++)
      if (vis[i][j])
        ans = min(ans, min(min(d(i), d(H - i - 1)), min(d(j), d(W - j - 1))));
  printf("%d\n", ans + 1);
}
