#define E(a)s[y][x]&3^a?d[y]+=s[x][y]=a,f(y,x+1),d[y]-=a:0
string s[6];int n,x,y,d[12],z=9;ll f(ll y,ll x){x-y||++x,x-n||(x=!++y),y-n?E(0),E(3):(coordcomp(n,d,d+n),z<?=d[n]);}{rd(n,s(n));f(0,0);wt(z+1);}