#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <cmath>
using namespace std;
const int N=810,M=N*N;
bool w[N][N];
char s[N][N];
int a[N],b[N],c[N],m1[4]={1,0,-1,0},m2[4]={0,1,0,-1};
inline int gi() {
    int x=0,o=1;
    char ch=getchar();
    while(ch!='-'&&(ch<'0'||ch>'9')) ch=getchar();
    if(ch=='-') o=-1,ch=getchar();
    while(ch>='0'&&ch<='9') x=x*10+ch-'0',ch=getchar();
    return x*o;
}
int main() {
    int n,m,k,ans=1<<30,x,y;
    cin>>n>>m>>k;
    for(int i=1;i<=n;i++) {
	scanf("%s",s[i]+1);
	for(int j=1;j<=m;j++)
	    if(s[i][j]=='S') x=i,y=j;
    }
    int t=0,sum=1;
    a[1]=x,b[1]=y,w[x][y]=1;
    while(t<sum) {
	x=a[++t],y=b[t];
	ans=min(ans,(min(min(x-1,n-x),min(y-1,m-y))+k-1)/k+1);
	if(c[t]==k) continue;
	for(int i=0;i<4;i++) {
	    int X=x+m1[i],Y=y+m2[i];
	    if(!w[X][Y]&&s[X][Y]=='.') {
		c[++sum]=c[t]+1,w[X][Y]=1;
		a[sum]=X,b[sum]=Y;
	    }
	}
    }
    cout<<ans;
    return 0;
}