#include <bits/stdc++.h>

 using namespace std;

 #define ll long long

 #define ull unsigned long long

 #define mst(a,b) memset((a),(b),sizeof(a))

 #define mp(a,b) make_pair(a,b)

 #define pi acos(-1)

 #define pii pair<int,int>

 #define pb push_back

 const int INF = 0x3f3f3f3f;

 const double eps = 1e-;

 const int MAXN = 2e5 + ;

 const int MAXM = 1e3 + ;

 const ll mod = 1e9 + ;

 char s[MAXN];

 int cnt[], dp[MAXN];

 int main() {

 #ifdef local

     freopen("data.txt", "r", stdin);

 #endif

     int t;

     scanf("%d",&t);

     while(t--) {

         int n,m,k;

         scanf("%d%d%d",&n,&m,&k);

         scanf("%s",s + );

         mst(cnt, );

         for(int i = ; i <= k; i++) cnt[s[i] - 'A' + ]++;

         ll ans = 1ll * n * m;

         for(int i = ; i <= ; i++) {

             for(int j = ; j <= k; j++) dp[j] = ;

             dp[] = ;

             for(int j = ; j <= ; j++) {

                 if(i == j) continue;

                 for(int h = k; h >= cnt[j]; h--) dp[h] |= dp[h - cnt[j]];

             }

             for(int j = ; j <= k; j++) {

                 if(!dp[j]) continue;

                 int x = max(, n - j), y = max(, m - (k - cnt[i] - j));

                 if(x + y <= cnt[i]) ans = min(ans, 1ll * x * y);

             }

         }

         printf("%lld\n",ans);

     }

     return ;

 }