#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
int t[10],ans,f[6][1<<10];
int read(){
    int res=0,op=1;char ch=getchar();
    while(!isdigit(ch)){if(ch=='-')op=-1;ch=getchar();}
    while(isdigit(ch))res=res*10+ch-'0',ch=getchar();
    return res*op;
}
int get(){
    int res;char ch=getchar();
    while(!isdigit(ch))ch=getchar();
    while(isdigit(ch)){res=ch;ch=getchar();}
    return res^48;
}
void write(ll x){
    if(x<0)putchar('-'),x=-x;
    if(x>9)write(x/10);
    putchar(x%10+48);
}
int play(int x,int y){
    int res=0;
    for(int i=0;i<=9;i++)if(((x>>i)&1)!=((y>>i)&1))res+=t[i];
    return res;
}
void solve(){
    int n=read();
    memset(t,0,sizeof(t));
    memset(f,0,sizeof(f));
    for(int i=1;i<=n;i++)t[get()]++;
    f[0][0]=n;
    for(int i=1;i<=5;i++)
    for(int j=0;j<(1<<10);j++)
    for(int k=j;k<(1<<10);k=k+1|j)
        f[i][k]=max(f[i][k],min(f[i-1][j],play(j,k)));
    ans=0;
    for(int j=0;j<(1<<10);j++)
        ans=max(ans,f[5][j]);
    write(n-ans);puts("");
}
int main()
{
    int es=read();
    while(es--)
    solve();
    return 0;
}