#include <string.h>
#include <algorithm>
#include <bitset>
#include <cassert>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <fstream>
#include <functional>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
// #include <unordered_map>
// #include <unordered_set>
#include <utility>
#include <vector>

#define pb push_back
#define mp make_pair

#ifdef ONLINE_JUDGE
#define link renamelink
#define next renamenext
#define prev renameprev
#endif

using namespace std;
typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int, int> pii;
typedef pair<LL, LL> pll;
typedef long double ld;

inline void EnableFileIO(const string& fileName, bool local = 0) {
  if (fileName.empty()) return;
  if (local) {
    freopen((fileName + ".in").c_str(), "r", stdin);
    freopen((fileName + ".out").c_str(), "w", stdout);
    return;
  }
#ifdef ONLINE_JUDGE
  freopen((fileName + ".in").c_str(), "r", stdin);
  freopen((fileName + ".out").c_str(), "w", stdout);
#endif
}

const int INF = (1 << 30) - 1;
const LL LINF = (1LL << 61) - 1;
const double EPS = 1e-10, PI = acos(-1);

int n, m, d;
char ans[567][789];

void out() {
  for (int x = 0; x < n; x++) {
    for (int y = 0; y < m; y++) {
      cout << ans[x][y];
    }
    cout << endl;
  }
}
void check() {
  for (int x = 0; x < n; x++) {
    for (int y = 0; y < m; y++) {
      assert(ans[x][y] != ' ');
      for (int xx = 0; xx < n; xx++) {
        for (int yy = 0; yy < m; yy++) {
          if (abs(x - xx) + abs(y - yy) == d) {
            assert(ans[x][y] != ans[xx][yy]);
          }
        }
      }
    }
  }
}
int dx[] = {1, 1, -1, -1};
int dy[] = {1, -1, 1, -1};
bool paint(int x, int y, char c) {
  if (x >= 0 && x < n && y >= 0 && y < m) {
    ans[x][y] = c;
    return 1;
  }
  return 0;
}
set<pii> vis;
void stamp(int x, int y, char c) {
  if (vis.count(mp(x, y))) return;
  if(x<-d || y<-d || x>n+d || y>m+d) return;
  vis.insert(mp(x, y));
  // cout<<x<<' '<<y<<' '<<c<<endl;
  bool ok = 0;
  for (int dec = 0; d - dec * 2 > 0; dec++) {
    for (int j = y + dec; j < y + d - dec; j++) {
      ok |= paint(x - dec, j, c);
      ok |= paint(x + dec, j, c);
    }
  }
  for (int k = 0; k < 4; k++) {
    stamp(x + dx[k] * d, y + dy[k] * d, c);
  }
}

int main() {
  // srand((int)time(0));
  // printf("Hello, world!\n");
  // EnableFileIO("");

  char id[] = {'R', 'G', 'B', 'Y'};

  cin >> n >> m >> d;

  /*
  for (int t = 0; t < 100; t++) {
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        if (ans[i][j] == 'A') {
          for (int ii = 0; ii < n; ii++) {
            int jj = j + d - abs(i - ii);
            if (jj >= 0 && jj < m) {
              ans[ii][jj] = 'B';
            }
            jj = j - d + abs(i - ii);
            if (jj >= 0 && jj < m) {
              ans[ii][jj] = 'B';
            }
          }
        }
      }
    }
  }
  for (int i = 0; i < n; i++) {
    for (int j = 0; j < m; j++) {
      if (ans[i][j] == 'A')
        cout << i << ' ' << j << ' ' << i + j << ' ' << i - j << ' ' << endl;
    }
  }
   */
  // stamp(d/2,d/2,'A');

  if (d & 1) {
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < m; j++) {
        if ((i + j) & 1) {
          cout << "R";
        } else {
          cout << "G";
        }
      }
      cout << endl;
    }
  } else {
    if (d % 4 == 2) {
      for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
          ans[i][j] = id[(j + ((i / 2) & 1) * 2) % 4];
        }
      }
    } else {
      for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) ans[i][j] = ' ';
      }
      stamp(0, 0, id[0]);
      stamp(d / 2, d / 2, id[1]);
      stamp(d / 2, -d / 2, id[2]);
      stamp(0, d, id[3]);
    }
    out();
    // check();
  }
  return 0;
}


Measured memory_bytes: 2432