#include <bits/stdc++.h>
using namespace std;
const int MX = 501;
int N, M, Q;
int r1, r2, c1, c2;
string str[MX];
vector<pair<int, int> > vt[MX];
vector<vector<int> > tree[251];
bool valid(int x, int y) { return x >= 0 && x < N && y >= 0 && y < M; }
void func(int x, int y, int len) {
  vt[len].push_back({x, y});
  x--, y--, len++;
  for (int i = 0; i < len; ++i) {
    if (!valid(x + i, y) || str[x + i][y] != 'R' || !valid(x, y + i) ||
        str[x][y + i] != 'R')
      return;
    if (!valid(x, y + 2 * len - 1 - i) || str[x][y + 2 * len - 1 - i] != 'G' ||
        !valid(x + i, y + 2 * len - 1) || str[x + i][y + 2 * len - 1] != 'G')
      return;
    if (!valid(x + 2 * len - 1 - i, y) || str[x + 2 * len - 1 - i][y] != 'Y' ||
        !valid(x + 2 * len - 1, y + i) || str[x + 2 * len - 1][y + i] != 'Y')
      return;
    if (!valid(x + 2 * len - 1 - i, y + 2 * len - 1) ||
        str[x + 2 * len - 1 - i][y + 2 * len - 1] != 'B' ||
        !valid(x + 2 * len - 1, y + 2 * len - 1 - i) ||
        str[x + 2 * len - 1][y + 2 * len - 1 - i] != 'B')
      return;
  }
  func(x, y, len);
}
void init(int tree_no, int node, int b, int e) {
  if (b == e) {
    tree[tree_no][node].push_back(vt[tree_no][b].second);
    return;
  }
  int l = 2 * node, r = l + 1, m = (b + e) / 2;
  init(tree_no, l, b, m);
  init(tree_no, r, m + 1, e);
  for (auto x : tree[tree_no][l]) tree[tree_no][node].push_back(x);
  for (auto x : tree[tree_no][r]) tree[tree_no][node].push_back(x);
  sort(tree[tree_no][node].begin(), tree[tree_no][node].end());
}
bool query(int tree_no, int node, int b, int e, int s, int f, int v1, int v2) {
  if (b > f || e < s) return 0;
  if (b >= s && e <= f) {
    auto it =
        lower_bound(tree[tree_no][node].begin(), tree[tree_no][node].end(), v1);
    if (it == tree[tree_no][node].end()) return 0;
    return (*it) <= v2;
  }
  int l = 2 * node, r = l + 1, m = (b + e) / 2;
  return (query(tree_no, l, b, m, s, f, v1, v2) ||
          query(tree_no, r, m + 1, e, s, f, v1, v2));
}
bool valid(int mid) {
  int i, j, k;
  int x1 = r1, y1 = c1, x2 = r2 - 2 * mid + 1, y2 = c2 - 2 * mid + 1;
  if (x2 < x1 || y2 < y1) return 0;
  int p1 = lower_bound(vt[mid].begin(), vt[mid].end(), make_pair(x1, -1)) -
           vt[mid].begin();
  int p2 = upper_bound(vt[mid].begin(), vt[mid].end(), make_pair(x2, MX)) -
           vt[mid].begin();
  if (p1 == p2) return 0;
  return query(mid, 1, 0, vt[mid].size() - 1, p1, p2 - 1, y1, y2);
}
void validate(int mid, int t) {
  int i, j, k;
  int x1 = r1, y1 = c1, x2 = r2 - 2 * mid + 1, y2 = c2 - 2 * mid + 1;
  int found = 0;
  int p1 = lower_bound(vt[mid].begin(), vt[mid].end(), make_pair(x1, -1)) -
           vt[mid].begin();
  int p2 = upper_bound(vt[mid].begin(), vt[mid].end(), make_pair(x2, MX)) -
           vt[mid].begin();
  for (i = p1; i < p2; ++i) {
    if (vt[mid][i].first >= x1 && vt[mid][i].first <= x2 &&
        vt[mid][i].second >= y1 && vt[mid][i].second <= y2)
      found = 1;
  }
  if (!found) {
    cout << "Test " << t << " : " << x1 << " " << y1 << " " << x2 << " " << y2
         << endl;
    cout << "Test " << t << " : " << r1 << " " << c1 << " " << r2 << " " << c2
         << endl;
    for (i = r1; i <= r2; ++i) {
      for (j = c1; j <= c2; ++j) cout << str[i][j];
      cout << endl;
    }
  }
  assert(found);
}
int main() {
  int i, j, k;
  scanf("%d %d %d", &N, &M, &Q);
  for (i = 0; i < N; ++i) cin >> str[i];
  for (i = 0; i < N - 1; ++i) {
    for (j = 0; j < M - 1; ++j) {
      if (str[i][j] == 'R' && str[i][j + 1] == 'G' && str[i + 1][j] == 'Y' &&
          str[i + 1][j + 1] == 'B')
        func(i, j, 1);
    }
  }
  for (i = 0; i <= N / 2; ++i) {
    if (vt[i].empty()) continue;
    sort(vt[i].begin(), vt[i].end());
    tree[i].clear();
    tree[i].resize(4 * int(vt[i].size()), vector<int>(0));
    init(i, 1, 0, vt[i].size() - 1);
  }
  for (i = 1; i <= Q; ++i) {
    scanf("%d %d %d %d", &r1, &c1, &r2, &c2);
    r1--, c1--, r2--, c2--;
    int low = 1, high = N / 2, ans = 0, mid;
    while (high >= low) {
      mid = (low + high) / 2;
      if (valid(mid)) {
        ans = mid;
        low = mid + 1;
      } else
        high = mid - 1;
    }
    cout << 4 * ans * ans << endl;
  }
}
