#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9 + 7;
struct fastio {
  char s[100000];
  int it, len;
  fastio() { it = len = 0; }
  inline char get() {
    if (it < len) return s[it++];
    it = 0;
    len = fread(s, 1, 100000, stdin);
    if (len == 0)
      return EOF;
    else
      return s[it++];
  }
  bool notend() {
    char c = get();
    while (c == ' ' || c == '\n') c = get();
    if (it > 0) it--;
    return c != EOF;
  }
} _buff;
inline long long getnum() {
  long long r = 0;
  bool ng = 0;
  char c;
  c = _buff.get();
  while (c != '-' && (c < '0' || c > '9')) c = _buff.get();
  if (c == '-') ng = 1, c = _buff.get();
  while (c >= '0' && c <= '9') r = r * 10 + c - '0', c = _buff.get();
  return ng ? -r : r;
}
template <class T>
inline void putnum(T x) {
  if (x < 0) putchar('-'), x = -x;
  register short a[20] = {}, sz = 0;
  while (x) a[sz++] = x % 10, x /= 10;
  if (sz == 0) putchar('0');
  for (int i = sz - 1; i >= 0; i--) putchar('0' + a[i]);
}
inline char getreal() {
  char c = _buff.get();
  while (c <= 32) c = _buff.get();
  return c;
}
long long qpow(long long x, long long k) {
  return k == 0 ? 1
                : 1ll * qpow(1ll * x * x % mod, k >> 1) * (k & 1 ? x : 1) % mod;
}
const int maxn = 200111;
int Tn;
int n, m, K;
int cnt[26];
int dp[maxn];
void add(int c) {
  if (c == 0) return;
  for (int i = K - c; i >= 0; i--) dp[i + c] += dp[i];
}
void del(int c) {
  if (c == 0) return;
  for (int i = 0; i <= K - c; i++) dp[i + c] -= dp[i];
}
int main() {
  Tn = getnum();
  while (Tn--) {
    n = getnum(), m = getnum(), K = getnum();
    memset(cnt, 0, sizeof(cnt));
    for (int i = 1; i <= K; i++) {
      char c = getreal();
      cnt[c - 'A']++;
    }
    for (int i = 0; i <= K; i++) dp[i] = 0;
    dp[0] = 1;
    for (int i = 0; i < 26; i++) add(cnt[i]);
    long long ans = 1e18;
    for (int i = 0; i < 26; i++) {
      del(cnt[i]);
      for (int j = 0; j <= K; j++) {
        if (dp[j]) {
          int x = j, y = K - cnt[i] - x;
          int xl = max(0, n - x);
          int yl = max(0, m - y);
          if (xl + yl > cnt[i]) continue;
          ans = min(ans, 1ll * xl * yl);
        }
      }
      add(cnt[i]);
    }
    cout << ans << endl;
  }
  return 0;
}
