#include <cstdio>
#include <algorithm>

using namespace std;

int Q[1010000][2], head, tail, D[810][810];
int n, m, K, sx, sy;
char p[810][810];

void Ins(int x, int y, int d) {
	if (D[x][y] <= d || p[x][y] != '.') return;
	D[x][y] = d;
	tail++;
	Q[tail][0] = x, Q[tail][1] = y; 
}

int main() {
	int i, j, x, y;
	scanf("%d%d%d", &n, &m, &K);
	for (i = 1; i <= n; i++) {
		scanf("%s", p[i] + 1);
		for (j = 1; j <= m; j++) {
			if (p[i][j] == 'S') sx = i, sy = j, p[i][j] = '.';
			D[i][j] = 1e9;
		}
	}
	Ins(sx, sy, 0);
	while (head < tail) {
		head++;
		x = Q[head][0], y = Q[head][1];
		Ins(x + 1, y, D[x][y] + 1);
		Ins(x, y + 1, D[x][y] + 1);
		Ins(x - 1, y, D[x][y] + 1);
		Ins(x, y - 1, D[x][y] + 1);
	}
	int res = 1e9;
	for (i = 1; i <= n; i++) {
		for (j = 1; j <= m; j++) {
			if (D[i][j] <= K) {
				res = min(res, 1 + (min(min(i - 1, n - i), min(j - 1, m - j)) + K - 1) / K);
			}
		}
	}
	printf("%d\n", res);
	return 0;
}