typedef long long ll;
typedef long double ld;
#include <bits/stdc++.h>
using namespace std;

int main() {
    ll h,w,k;
    std::cin >> h>>w>>k;
    
    vector<string> a(h);
    pair<ll,ll> s;
    for (int i = 0; i < h; i++) {
        std::cin >> a[i];
        for (int j = 0; j < w; j++) {
            if(a[i][j]=='S')s = {i,j};
        }
    }
    
    set<pair<ll,ll>> se;
    
    queue<tuple<ll,ll,ll>> q;
    q.push({s.first,s.second,k});
    se.insert({s.first,s.second});
    while(q.size()){
        auto [xx,yy,rem] = q.front();q.pop();
        if(rem==0)continue;
        for (int x = -1, y = 0, iii = 0; iii < 4; x += y, y = x - y, x = y - x, ++iii) {
            if(xx+x<0||xx+x>h-1||yy+y<0||yy+y>w-1)continue;
            if(a[xx+x][yy+y]=='.'){
                if(se.find({xx+x,yy+y})!=se.end())continue;
                if(rem-1>0)q.push({xx+x,yy+y,rem-1});
                se.insert({xx+x,yy+y});
            }
        }
    }
    ll ans = 1e15;
    for (auto e : se) {
        auto minx = min(e.first,h-1-e.first);
        auto miny = min(e.second,w-1-e.second);
        ans = min(ans, (min(minx,miny)+k-1)/k);
    }
    std::cout << 1+ans << std::endl;
}
