#include<bits/stdc++.h>
using namespace std;
struct node{
	int x,y,val,prex,prey;
	bool operator<(node x)const{
		return val>x.val;
	}
	bool operator>(node x)const{
		return val<x.val;
	}
};
const int d[4][2]={{1,0},{-1,0},{0,1},{0,-1}};
int n,sx,sy,ex,ey;
priority_queue<node> q;
int vis[114][114],dis[114][114];
char a[114][114];
void bfs(int sx,int sy){
	vis[sx][sy]=1;
	dis[sx][sy]=0;
	q.push(node{sx,sy,0,0,0});
	while(!q.empty()){
		node now=q.top();q.pop();
		for(int i=0;i<4;i++){
			int nx=now.x+d[i][0],ny=now.y+d[i][1];
			if(nx>0&&nx<=n&&ny>0&&ny<=n&&a[nx][ny]!='x'&&!vis[nx][ny]){
				int dist=0;
				if(now.prex==0&&now.prey==0)dist=0;
				else if(now.prex==now.x)dist=(nx!=now.prex);
				else if(now.prey==now.y)dist=(ny!=now.prey);
				if(dis[nx][ny]>=dis[now.x][now.y]+dist){
					vis[nx][ny]=1;
					dis[nx][ny]=dis[now.x][now.y]+dist;
					q.push({nx,ny,dis[nx][ny],now.x,now.y});
				}
			}
		}
	}
	return;
}
int main(){
	cin>>n;
	for(int i=1;i<=n;i++){
		for(int j=1;j<=n;j++){
			cin>>a[i][j];
			if(a[i][j]=='A'){
				sx=i,sy=j;
			}else if(a[i][j]=='B'){
				ex=i,ey=j;
			}
		}
	}
	memset(dis,63,sizeof(dis));
	bfs(sx,sy);
	if(vis[ex][ey]==0)cout<<-1;
	else cout<<dis[ex][ey];
	return 0;
}

WA on #4 #8 #10