#include <queue>
#include <iostream>
using namespace std;
int main() {
    int h, w, k; cin >> h >> w >> k;
    string s[h]; for (int i = 0; i < h; i++) cin >> s[i];
    int sx, sy;
    for (int x = 0, done = 0; x < h && !done; x++)
        for (int y = 0; y < w && !done; y++)
            if (s[x][y] == 'S') { sx = x; sy = y; done = 1; }
    priority_queue<pair<int, pair<int, int> > > pq;
    pq.push({0, {sx, sy}});
    int dist[h][w];
    for (int i = 0; i < h; i++) fill(dist[i], dist[i]+w, 1<<30);
    dist[sx][sy] = 0;
    int dx[] = {0, 1, 0, -1}, dy[] = {1, 0, -1, 0};
    for (;;) {
        int d = -pq.top().first,
            x = pq.top().second.first, y = pq.top().second.second;
        pq.pop();
        if (d > dist[x][y]) continue;
        if (x == 0 || x == h-1 || y == 0 || y == w-1) {
            cout << (d + k - 1) / k << endl;
            return 0;
        }
        for (int i = 0; i < 4; i++) {
            int x1 = x + dx[i], y1 = y + dy[i];
            int d1 = (s[x1][y1] == '#' && d < k ? k+1 : d+1);
            if (dist[x1][y1] <= d1) continue;
            dist[x1][y1] = d1;
            pq.push({-d1, {x1, y1}});
        }
    }
}
