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

const int MAXN = 805;

struct point {
	int x, y, d;
};

int dx[] = {1, 0, -1, 0}, dy[] = {0, 1, 0, -1};

int n, m, k;
char str[MAXN][MAXN];
int vis[MAXN][MAXN];

int main()
{
	ios::sync_with_stdio(false);
	cin >> n >> m >> k;
	for (int i = 1; i <= n; i++)
		cin >> str[i]+1;
	point rt;
	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= m; j++)
			if (str[i][j] == 'S')
				rt = (point){i, j, 0};
	static queue<point> que;
	int ans = INT_MAX;
	auto div_up = [](int a, int b){ return a/b+(a%b!=0); };
	vis[rt.x][rt.y] = 1, que.push(rt);
	while (!que.empty()) {
		point nd = que.front(); que.pop();
		if (nd.d > k) continue;
		ans = min(ans, div_up(min(min(nd.x-1, n-nd.x), min(nd.y-1, m-nd.y)), k)+1);
		for (int i = 0; i < 4; i++) {
			int x = nd.x+dx[i], y = nd.y+dy[i];
			if (x < 1 || x > n || y < 1 || y > m || str[x][y] == '#' || vis[x][y]) continue;
			vis[x][y] = 1;
			que.push((point){x, y, nd.d+1});
		}
	}
	cout << ans << endl;
	return 0;
}
