#include <iostream>
#include <cmath>
using namespace std;

const int maxn = 808;
int n, m, k, sx, sy, ans = maxn,  bio[maxn][maxn];
char c[maxn][maxn];
int dx[] = {-1, 0, 1, 0}, dy[] = {0, 1, 0, -1};

void solve(int x, int y){
	bio[x][y] = true;

	if(abs(x - sx) + abs(y - sy) > k){
		return;
	}

	for(int i = 0; i < 4; i++){
		int nx = x + dx[i], ny = y + dy[i];

		if(x >= 1 && x <= n && y >= 1 && y <= m && !bio[nx][ny] && c[nx][ny] == '.'){
			solve(nx, ny);
		}
	}

	int d = min(min(x - 1, n - x), min(y - 1, m - y));
	int tmp = d / k + bool(d % k);

	ans = min(ans, tmp);
}

int main(){
	ios_base::sync_with_stdio(false);

	cin >> n >> m >> k;

	for(int i = 1; i <= n; i++){
		for(int j = 1; j <= m; j++){
			cin >> c[i][j];

			if(c[i][j] == 'S'){
				sx = i, sy = j;
			}
		}
	}

	solve(sx, sy);

	cout << ans + 1 << endl;

	return 0;
}
