#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<queue>
using namespace std;
const int INF=0x7fffffff/2;
const int SIZEN=110;
int F[SIZEN][SIZEN][SIZEN][5];
bool inque[SIZEN][SIZEN][SIZEN][5];
class State{
public:
	int x,y;
	int rem,dir;
	int& val(void){
		return F[x][y][rem][dir];
	}
	bool& inq(void){
		return inque[x][y][rem][dir];
	}
};
int dx[]={0,0,0,1,-1},dy[]={0,1,-1,0,0};
int N,M,D;
char board[SIZEN][SIZEN];
queue<State> Q;
inline void check(State s,int w){
	//cout<<s.x<<" "<<s.y<<" "<<s.rem<<" "<<s.dir<<" "<<w<<endl;
	if(w<s.val()){
		s.val()=w;
		if(!s.inq()){
			s.inq()=true;
			Q.push(s);
		}
	}
}
void work(void){
	for(int i=0;i<SIZEN;i++){
		for(int j=0;j<SIZEN;j++){
			for(int r=0;r<SIZEN;r++){
				for(int d=0;d<5;d++) F[i][j][r][d]=INF;
			}
		}
	}
	memset(inque,0,sizeof(inque));
	while(!Q.empty()) Q.pop();
	State start;start.x=1,start.y=1,start.rem=D,start.dir=0;
	start.val()=0;
	start.inq()=true;
	Q.push(start);
	State s,t;
	while(!Q.empty()){
		//cout<<Q.size()<<endl;
		s=Q.front();Q.pop();s.inq()=false;int w=s.val();
		//cout<<s.x<<" "<<s.y<<" "<<s.rem<<" "<<s.dir<<" "<<w<<endl;
		if(s.dir!=0){//在半空中
			//转移1:停下
			if(board[s.x][s.y]=='P'){
				t=s;
				t.dir=0;
				check(t,w);
			}
			//转移2:继续飞
			t=s;
			t.x+=dx[s.dir],t.y+=dy[s.dir];t.rem--;
			if(1<=t.x&&t.x<=N&&1<=t.y&&t.y<=M&&t.rem>=0) check(t,w);
		}
		else{//在地面上
			//走路
			for(int d=1;d<=4;d++){
				t=s;
				t.x+=dx[d],t.y+=dy[d];
				//cout<<t.x<<" "<<t.y<<" "<<board[t.x][t.y]<<endl;
				if(1<=t.x&&t.x<=N&&1<=t.y&&t.y<=M&&board[t.x][t.y]=='P') check(t,w+1);
			}
			//向四个方向起飞
			for(int d=1;d<=4;d++){
				t=s;t.dir=d;
				check(t,w+1);
			}
		}
		//cout<<Q.size()<<endl;
	}
	int ans=INF;
	for(int i=0;i<=D;i++){
		ans=min(ans,F[N][M][i][0]);
	}
	if(ans==INF) printf("impossible\n");
	else printf("%d\n",ans);
}
void read(void){
	scanf("%d%d%d",&N,&M,&D);
	for(int i=1;i<=N;i++){
		scanf("%s",board[i]+1);
	}
}
int main(){
	freopen("escapea.in","r",stdin);
	freopen("escapea.out","w",stdout);
	read();
	work();
	return 0;
}