#include <bits/stdc++.h>

using namespace std;

#define pb push_back
#define mp make_pair
#define forn(i, n) for (int i = 0; i < (int)(n); ++i)
typedef long long LL;
typedef pair<int, int> PII;

const char c[4] = {'R', 'Y', 'G', 'B'};
int h, w, d;
char s[500][501];

int main() {
    cin >> h >> w >> d;
    forn(i, h) forn(j, w) {
        int cur = 0;
        cur += ((i + j) / d) & 1;
        cur += (((i + w - 1 - j) / d) & 1) << 1;
        assert(cur >= 0 && cur < 4);
        s[i][j] = c[cur];
    }
    forn(i, h) printf("%s\n", s[i]);
    return 0;
}
