#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
#define Rep(i,a,b) for(register int i=(a);i<=(b);++i)
#define rep(i,a,b) for(register int i=(a);i<(b);++i)
#define Dep(i,a,b) for(register int i=(a);i>=(b);--i)
#define mem(x,v) memset(x,v,sizeof(x))
#define gc getchar
#define pc putchar
inline ll read(){
    ll x = 0,f = 0;char c = gc();
    for(;!isdigit(c);c=gc()) f|=(c=='-');
    for(;isdigit(c);c=gc()) x = x * 10 + (c - '0');
    return f ? -x : x;
}
inline void write(ll x){if(x < 0) pc('-'),x=-x;if(x>=10) write(x / 10);pc(x%10+'0');}
inline void writeln(ll x){write(x),pc('\n');}
inline void wri(ll x){write(x),pc(' ');}
const int maxn = 1e6+233;
int f[10][1<<10],g[1<<10],n,cnt[233];
char s[2333];
void solve(){
    n = read();
    Rep(i,0,9) cnt[i] = 0;
    Rep(i,1,n){
        scanf("%s",s);
        cnt[s[4]-'0']++;
    }
    memset(f,0x3f,sizeof(f));
    rep(i,0,1<<10){
        g[i] = 0;
        Rep(j,0,9) if(!(i>>j&1)) g[i] += cnt[j];
    }
    f[0][0] = 0;
    Rep(len,0,5){
        rep(i,0,1<<10){
            for(int j=i;;j=(j-1)&i){
                f[len+1][i] = min(f[len+1][i],max(f[len][j],g[i^j]));
                if(!j) break;
            }
        }
    }
    int ans = 0x3f3f3f3f;
    rep(i,0,1<<10) ans = min(ans,f[5][i]);
    writeln(ans);
    /*sum=0;
    Rep(i,0,9) sum+=cnt[i];
    Rep(i,0,9) cnt[i]=sum-cnt[i];
    sort(cnt+0,cnt+9+1);
    writeln(cnt[4]);*/
}
int main(){
//    freopen("1.in","r",stdin);
    int T = read();
    while(T--) solve();
    return 0;
}