#include<bits/stdc++.h>
using namespace std;

int H,W,K,Sx,Sy,dis[810][810],dep[810][810],Ans=1e9;
bool g[810][810],vis[810][810];
queue<pair<int,int> > q;

void BFS()
{
	while (!q.empty()) q.pop();
	vis[Sx][Sy]=1;
	q.push(make_pair(Sx,Sy));
	while (!q.empty())
	{
		int x=q.front().first;
		int y=q.front().second;
		q.pop();
		Ans=min(Ans,dis[x][y]+1);
		if (dep[x][y]==K) continue;
		if (g[x-1][y]&&!vis[x-1][y]) dep[x-1][y]=dep[x][y]+1,vis[x-1][y]=1,q.push(make_pair(x-1,y));
		if (g[x+1][y]&&!vis[x+1][y]) dep[x+1][y]=dep[x][y]+1,vis[x+1][y]=1,q.push(make_pair(x+1,y));
		if (g[x][y-1]&&!vis[x][y-1]) dep[x][y-1]=dep[x][y]+1,vis[x][y-1]=1,q.push(make_pair(x,y-1));
		if (g[x][y+1]&&!vis[x][y+1]) dep[x][y+1]=dep[x][y]+1,vis[x][y+1]=1,q.push(make_pair(x,y+1));
	}
}

int main()
{
#ifdef h10
	freopen("C.in","r",stdin);
	freopen("C.out","w",stdout);
#endif
	int i,j;
	char c;
	scanf("%d%d%d",&H,&W,&K);
	for (i=1;i<=H;i++)
	for (j=1;j<=W;j++)
	{
		c=getchar();
		while (c!='.'&&c!='#'&&c!='S') c=getchar();
		if (c=='#') continue;
		g[i][j]=1;
		dis[i][j]=min(min((i-1+K-1)/K,(j-1+K-1)/K),min((H-i+K-1)/K,(W-j+K-1)/K));
		if (c=='S') Sx=i,Sy=j;
	}
	BFS();
	printf("%d\n",Ans);
}
