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

int n,a[110][110];
char aa[110][110];
int sx,sy,ex,ey,f;
int ans;

const int fx[4] = {-1,0,0,1};
const int fy[4] = {0,-1,1,0};

void dfs(int x,int y,int t,int k)
{
	if (ans <= k) return ;
	if (x == ex && y == ey) {ans = min(ans,k);f = 1;return ;}
	for (int i = 0;i < 4;i++)
	{
		int xx = x + fx[i],yy = y + fy[i];
		if (xx >= 1 && xx <= n && yy >= 1 && yy <= n && a[xx][yy])
		{
			a[xx][yy] = 0;
			int now = 0;
			if (i != t)
				now = 1;
			if (t == -1)
				now = 0;
			dfs(xx,yy,i,k+now);
			a[xx][yy] = 1;
		}
	}
}

void solve()
{
	ans = 2e9;
	scanf("%lld",&n);
	for (int i = 1;i <= n;i++)
		for (int j = 1;j <= n;j++)
		{
			cin >> aa[i][j];
			if (aa[i][j] == '.')
				a[i][j] = 1;
			if (aa[i][j] == 'A')
				sx = i,sy = j;
			if (aa[i][j] == 'B')
				ex = i,ey = j,a[i][j] = 1;
		}
	dfs(sx,sy,-1,0);
	if (f) printf("%lld",ans);
	else printf("-1");
}

signed main()
{
	solve();
	printf("\n");
	return 0;
}