#include<bits/stdc++.h>

using namespace std;

int x, y, N, M, K, d[809][809];
char sir[809][809];
queue < pair < int, int > > cc;
int dx[] = {-1, 1, 0, 0};
int dy[] = {0, 0, -1, 1};

int main ()
{
//freopen ("input", "r", stdin);
//freopen ("output", "w", stdout);

scanf ("%d %d %d\n", &N, &M, &K);
for (int i=1; i<=N; i++)
{
    scanf ("%s", sir[i] + 1);
    for (int j=1; j<=M; j++)
    {
        if (sir[i][j] == 'S')
            x = i, y = j, sir[i][j] = '.';
        d[i][j] = -1;
    }
}
d[x][y] = 0;
cc.push ({x, y});
while (!cc.empty ())
{
    auto curr = cc.front ();
    cc.pop ();
    for (int k=0; k<4; k++)
    {
        int x = curr.first + dx[k], y = curr.second + dy[k];
        if (sir[x][y] == '.' && d[x][y] == -1)
            d[x][y] = d[curr.first][curr.second] + 1,
            cc.push ({x, y});
    }
}
int ans = 2 * N + 2 * M + 2 * K;
for (int i=1; i<=N; i++)
    for (int j=1; j<=M; j++)
        if (d[i][j] != -1 && d[i][j] <= K)
        {
            int fromHere = min (min (i - 1, N - i), min (j - 1, M - j)), t = fromHere / K + (fromHere % K != 0);
            if (t + 1 < ans)
                ans = t + 1;
        }
printf ("%d\n", ans);
return 0;
}
