#include<bits/stdc++.h>
#define N 805
using namespace std;
queue<int> P,Q,D;
int n,m,k,u,v,B[N][N],ans=(1<<30); char A[N][N];
void ins(int x,int y,int z){ if(z>k||B[x][y]) return ; P.push(x),Q.push(y),D.push(z),B[x][y]=1;}
void flood()
{
	int x,y,z;
	P.push(u),Q.push(v),D.push(0),B[u][v]=1;
	while(!P.empty()){
		x=P.front(),y=Q.front(),z=D.front();
		P.pop(),Q.pop(),D.pop();
		if(x>1&&!B[x-1][y]&&A[x-1][y]!='#') ins(x-1,y,z+1);
		if(y>1&&!B[x][y-1]&&A[x][y-1]!='#') ins(x,y-1,z+1);
		if(x<n&&!B[x+1][y]&&A[x+1][y]!='#') ins(x+1,y,z+1);
		if(y<m&&!B[x][y+1]&&A[x][y+1]!='#') ins(x,y+1,z+1);
	  }
}
int main()
{
	int i,j;
	scanf("%d %d %d\n",&n,&m,&k);
	for(i=1;i<=n;i++) scanf("%s",A[i]+1);
	for(i=1;i<=n;i++)
		for(j=1;j<=m;j++)
			if(A[i][j]=='S') u=i,v=j;
	flood();
	for(i=1;i<=n;i++)
		for(j=1;j<=m;j++)
			if(B[i][j])
				ans=min((min(min(j-1,m-j),min(i-1,n-i))+k-1)/k+1,ans);
	cout<<ans;
	return 0;
}
