macro_rules ! input { ( source = $ s : expr , $ ( $ r : tt ) * ) => { let mut iter = $ s . split_whitespace ( ) ; input_inner ! { iter , $ ( $ r ) * } } ; ( iter = $ iter : ident , $ ( $ r : tt ) * ) => { let s = { use std :: io :: Read ; let mut s = String :: new ( ) ; std :: io :: stdin ( ) . read_to_string ( & mut s ) . unwrap ( ) ; s } ; let mut $ iter = s . split_whitespace ( ) ; input_inner ! { $ iter , $ ( $ r ) * } } ; ( $ ( $ r : tt ) * ) => { let s = { use std :: io :: Read ; let mut s = String :: new ( ) ; std :: io :: stdin ( ) . read_to_string ( & mut s ) . unwrap ( ) ; s } ; let mut iter = s . split_whitespace ( ) ; input_inner ! { iter , $ ( $ r ) * } } ; }
macro_rules ! input_inner { ( $ iter : expr ) => { } ; ( $ iter : expr , ) => { } ; ( $ iter : expr , mut $ var : ident : $ t : tt $ ( $ r : tt ) * ) => { let mut $ var = read_value ! ( $ iter , $ t ) ; input_inner ! { $ iter $ ( $ r ) * } } ; ( $ iter : expr , mut $ var : ident $ ( $ r : tt ) * ) => { input_inner ! { $ iter , mut $ var : usize $ ( $ r ) * } } ; ( $ iter : expr , $ var : ident : $ t : tt $ ( $ r : tt ) * ) => { let $ var = read_value ! ( $ iter , $ t ) ; input_inner ! { $ iter $ ( $ r ) * } } ; ( $ iter : expr , $ var : ident $ ( $ r : tt ) * ) => { input_inner ! { $ iter , $ var : usize $ ( $ r ) * } } ; }
macro_rules ! read_value { ( $ iter : expr , ( $ ( $ t : tt ) ,* ) ) => { ( $ ( read_value ! ( $ iter , $ t ) ) ,* ) } ; ( $ iter : expr , [ $ t : tt ; $ len : expr ] ) => { ( 0 ..$ len ) . map ( | _ | read_value ! ( $ iter , $ t ) ) . collect ::< Vec < _ >> ( ) } ; ( $ iter : expr , { chars : $ base : expr } ) => { read_value ! ( $ iter , String ) . chars ( ) . map ( | c | ( c as u8 - $ base as u8 ) as usize ) . collect ::< Vec < usize >> ( ) } ; ( $ iter : expr , { char : $ base : expr } ) => { read_value ! ( $ iter , { chars : $ base } ) [ 0 ] } ; ( $ iter : expr , chars ) => { read_value ! ( $ iter , String ) . chars ( ) . collect ::< Vec < char >> ( ) } ; ( $ iter : expr , char ) => { read_value ! ( $ iter , chars ) [ 0 ] } ; ( $ iter : expr , usize1 ) => { read_value ! ( $ iter , usize ) - 1 } ; ( $ iter : expr , $ t : ty ) => { $ iter . next ( ) . unwrap ( ) . parse ::<$ t > ( ) . unwrap ( ) } ; }
#[derive(Eq, PartialEq, Clone, Copy, Debug)]
pub struct Rev<T>(pub T);
impl<T: PartialOrd> PartialOrd for Rev<T> {
    fn partial_cmp(&self, other: &Rev<T>) -> Option<std::cmp::Ordering> {
        other.0.partial_cmp(&self.0)
    }
}
impl<T: Ord> Ord for Rev<T> {
    fn cmp(&self, other: &Rev<T>) -> std::cmp::Ordering {
        other.0.cmp(&self.0)
    }
}
use std::collections::BinaryHeap;
fn main() {
    input! { h, w, k, a: [chars; h] };
    let mut start = (0, 0);
    for i in 0..h {
        for j in 0..w {
            if a[i][j] == 'S' {
                start = (i, j);
            }
        }
    }
    let mut heap = BinaryHeap::new();
    let mut visited = vec![vec![false; w]; h];
    visited[start.0][start.1] = true;
    heap.push(Rev((1, 0, Rev(0), start)));
    let dir = vec![1, 0, -1, 0, 1];
    while let Some(u) = heap.pop() {
        let (mut m, mut l, mut p, u) = u.0;
        if u.0 == 0 || u.0 == h - 1 || u.1 == 0 || u.1 == w - 1 {
            println!("{}", m);
            break;
        }
        if l == k {
            l = 0;
            m += 1;
            p.0 += k;
        }
        for i in 0..4 {
            let (dx, dy) = (dir[i], dir[i + 1]);
            let v = ((u.0 as isize + dx) as usize, (u.1 as isize + dy) as usize);
            if !visited[v.0][v.1] {
                if a[v.0][v.1] == '#' {
                    if p.0 > 0 {
                        visited[v.0][v.1] = true;
                        heap.push(Rev((m, l + 1, Rev(p.0 - 1), v)));
                    } else {
                        visited[v.0][v.1] = true;
                        heap.push(Rev((m + 1, 0, Rev(k - 1), v)));
                    }
                } else {
                    visited[v.0][v.1] = true;
                    heap.push(Rev((m, l + 1, p, v)));
                }
            }
        }
    }
}
