#include <iostream>
#include <cstdio>
#include <bitset>
using namespace std;
int t;
int n, m, k;
char s[200010];
int tot[30];
bool dp[200010];
int main()
{
	scanf("%d", &t);
	while(t --)
	{
		scanf("%d%d%d", &n, &m, &k);
		if(n < m)swap(n, m);
		scanf("%s", s + 1);
		for (int i = 0; i <= 26; ++ i)
		tot[i] = 0;
		for (int i = 1; i <= k; ++ i)
		{
			++ tot[s[i] - 'A'];
		}
		long long ans = 1e18;
		for (int i = 0; i <= 25; ++ i)
		{
			for (int i = 1; i <= n; ++ i)
			dp[i] = 0;
			dp[0] = 1;
			for (int j = 0; j <= 25; ++ j)
			{
				if(i == j)continue;
				for (int i = n; i >= tot[j]; -- i)
				dp[i] |= dp[i - tot[j]];
//				cout << dp << endl;
			}
			for (int j = 0; j <= min(n, tot[i]); ++ j)
			if(dp[n - j])
			ans = min(ans, 1ll * j * (max(0, tot[i] - j - (k - n - m))));
		}
		printf("%lld\n", ans);
	}
}