#include <iostream>
#include <cstdio>
#include <cstring>
#define ll long long
#define INF (1ll<<60ll)
using namespace std;
ll T,m,n,K,dy,cnt[27],ans;
char str[200100];
bool dp[200100];
signed main()
{
    register ll i,j,k;
    scanf("%lld",&T);
    dp[0]=1;
    while(T--)
	{
		scanf("%lld%lld%lld%s",&m,&n,&K,&str[1]);
        memset(cnt,0,sizeof cnt);
        ans=INF;
        dy=K-m-n;
        if(m>n)swap(m,n);
        for(i=1;i<=K;i++)cnt[str[i]-'A'+1]++;
        for(i=1;i<=26;i++)
		{
            for(j=1;j<=n;j++)dp[j]=0;
            for(j=1;j<=26;j++){if(i==j)continue;for(k=n;k>=cnt[j];k--)dp[k]|=dp[k-cnt[j]];}
            for(j=min(cnt[i],n);j>=0;j--){if(!dp[n-j])continue; ans=min(ans,j*max(0ll,cnt[i]-j-dy));}
        }
        printf("%lld\n",ans);
    }
    return 0;
}