#include <bits/stdc++.h>
using namespace std;

int H, W, K, dir[4][2] = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
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);
		
}

