graph

#include<bits/stdc++.h>
#define nl "\n"
#define fi first
#define se second
#define pi 3.14159
#define ll long long
#define odd(a)  (a&1)
#define even(a)  !(a&1)
#define Mod 1'000'000'007
#define INF 2'000'000'000 // 2e9
#define sz(x) int(x.size())
#define charToInt(s) (s - '0')
#define ull unsigned long long
#define number_line iota(all(vec) , 1)
#define all(s) s.begin(), s.end()
#define rall(v) v.rbegin() , v.rend()
#define fixed(n) fixed << setprecision(n)
#define Num_of_Digits(n) ((int)log10(n) + 1)
#define to_decimal(bin) stoll(bin, nullptr, 2)
#define Ceil(n, m) (((n) / (m)) + ((n) % (m) ? 1 : 0))
#define Floor(n, m) (((n) / (m)) - ((n) % (m) ? 0 : 1))
#define Upper(s) transform(all(s), s.begin(), ::toupper);
#define Lower(s) transform(all(s), s.begin(), ::tolower);
#define cout_map(mp) for(auto& [f, s] : mp) cout << f << "  " << s << "\n";
//  ----- bits-------
#define pcnt(n) __builtin_popcount(n)
#define pcntll(n) __builtin_popcountll(n)
#define clz(n) __builtin_clz(n)    // <---100
#define clzll(n) __builtin_clzll(n)
#define ctz(n) __builtin_ctz(n)  // 0001---->
#define ctzll(n) __builtin_ctzll(n)

using namespace std;

template < typename T = int > istream& operator >> (istream &in, vector < T > & v){
    for(auto & x : v) in >> x;
    return in;
}

template < typename T = int > ostream& operator << (ostream &out, const vector < T > & v){
    for(const T & x : v) out << x << " ";
    return out;
}

void esraa()
{
    ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
#endif
}

struct node{
    int i , j , cnt;

    node(int i , int j , int cnt) : i(i) , j(j) , cnt(cnt) {}
};

int dx[] = {0 , 0 , 1 , -1};
int dy[] = {1 , -1 , 0 , 0};
void solve(){
    int n , m , d;
    cin >> n >> m >> d;
    vector < string > v(n);
    for(auto & i : v) cin >> i;

    auto valid = [&](int x , int y){
        return x >= 0 and x < n and y >= 0 and y < m and v[x][y] != 'M';
    };

    int sx , sy , fx , fy;

    for(int i = 0; i < n; i++){
        for(int j = 0; j < m; j++){
            if(v[i][j] == 'S') sx = i , sy = j;
            if(v[i][j] == 'F') fx = i , fy = j;
        }
    }

    auto bfs1 = [&](){
        queue < node > q;

        for(int i = 0; i < n; i++){
            for(int j = 0; j < m; j++){
                if(v[i][j] == 'M') q.push(node(i , j , d));
            }
        }

        while(!q.empty()){
            auto [i , j , cnt] = q.front();
            q.pop();

            if(cnt <= 0) continue;

            for(int k = 0; k < 4; k++){
                int x = i + dx[k];
                int y = j + dy[k];

                if(valid(x , y)){
                    v[x][y] = 'M';
                    q.push(node(x , y , cnt - 1));
                }
            }


        }
    };

    bfs1();

    auto bfs2 = [&](){
        vector < vector < bool > > vis(n , vector < bool > (m));
        queue < node > q;
        for(int i = 0; i < n; i++){
            for(int j = 0; j < m; j++){
                if(v[i][j] == 'S') q.push(node(i , j , 0));
            }
        }

        vis[sx][sy] = true;

        while(!q.empty()){
            auto [i , j , cnt] = q.front();
            q.pop();

            if(v[i][j] == 'F') return cnt;

            for(int k = 0; k < 4; k++){
                int x = i + dx[k];
                int y = j + dy[k];

                if(valid(x , y) and !vis[x][y]){
                    vis[x][y] = true;
                    q.push(node(x , y , cnt + 1));
                }
            }
        }

        return -1;
    };

    cout << bfs2() << nl;


}
int main()
{
    esraa();
    int t = 1;
    // cin >> t;
    //cin.ignore();
    while(t--)
        solve();
    return 0;
}