#include<bits/stdc++.h>
using namespace std;
int H, W, K;
int MAP[1000][1000];
int x, y, vis[1000][1000];
int ans = 2147483647;
const int dx[4] = {0, 1, 0, -1};
const int dy[4] = {1, 0, -1, 0};
struct PR {
int x, y, now;
PR() {x = y = now = 0;}
PR(int _x, int _y, int _now) {x = _x, y = _y, now = _now;}
};
bool check(int x, int y) {
if (x < 0 || x > H) return 0;
if (y < 0 || y > W) return 0;
if (MAP[x][y]) return 0;
return 1;
}
int main() {
cin >> H >> W >> K;
for (int i = 1; i <= H; i ++) {
string s;
cin >> s;
for (int j = 1; j <= W; j ++) {
if (s[j - 1] == '#') MAP[i][j] = 1;
else {
MAP[i][j] = 0;
if (s[j - 1] == 'S') x = i, y = j;
}
}
}
queue<PR> Q; Q.push((PR){x, y, 0});
while (!Q.empty()) {
PR tmp = Q.front(); Q.pop();
if (tmp.now > K) continue;
if (vis[tmp.x][tmp.y] <= tmp.now && vis[tmp.x][tmp.y] != 0) continue;
vis[tmp.x][tmp.y] = tmp.now;
int num = min(min(H - tmp.x, W - tmp.y), min(tmp.x - 1, tmp.y - 1));
num = (num + K - 1) / K;
if (num + 1 > ans) continue;
ans = min(ans, num + 1);
for (int i = 0; i < 4; i ++) {
if (check(tmp.x + dx[i], tmp.y + dy[i])) Q.push((PR){tmp.x + dx[i], tmp.y + dy[i], tmp.now + 1});
}
}
cout << ans << endl;
return 0;
}