/**
 * code generated by JHelper
 * More info: https://github.com/AlexeyDmitriev/JHelper
 * @author
 */

#ifndef MAJK_LIB
#define MAJK_LIB

#include <vector>
#include <stack>
#include <iostream>
#include <unordered_map>
#include <map>
#include <iomanip>
#include <set>
#include <functional>
#include <fstream>
#include <algorithm>
#include <cassert>
#include <cmath>
#include <string>
#include <sstream>
#include <queue>
#include <bitset>
using namespace std;

#define x first
#define y second
constexpr int MOD = 1000000007;

typedef std::pair<int,int> pii;
typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int ui;

template <typename T, typename U> std::istream&operator>>(std::istream&i, pair<T,U>&p) {i >> p.x >> p.y; return i;}
template<typename T>std::istream&operator>>(std::istream&i,vector<T>&t) {for(auto&v:t){i>>v;}return i;}
template<typename T>std::ostream&operator<<(std::ostream&o,const vector<T>&t) {for(size_t i=0;i<t.size();++i){o<<t[i]<<" \n"[i == t.size()-1];}return o;}
template<typename T> using minheap = priority_queue<T, vector<T>, greater<T>>;
template<typename T> using maxheap = priority_queue<T, vector<T>, less<T>>;
auto fraclt = [](const pii&a,const pii&b) { return (ll)a.x * b.y < (ll)b.x * a.y; };
struct cmpfrac { bool operator()(const pii&a,const pii&b)const { return (ll)a.x * b.y < (ll)b.x * a.y; }};
template <typename T> bool in(T a, T b, T c) { return a <= b && b < c; }
ui logceil(ll x) {ui b=0;while(x){x>>=1;++b;}return b;}

namespace std {
    template<typename T,typename U>struct hash<pair<T,U>>{hash<T>t;hash<U>u;size_t operator()(const pair<T,U>&p)const{return t(p.x)^(u(p.y)<<7);}};
}
template<typename T,typename F>T bsh(T l,T h,const F&f){T r=-1,m;while(l<=h){m=(l+h)/2;if(f(m)){l=m+1;r=m;}else{h=m-1;}}return r;}
template<typename T,typename F>T bsl(T l,T h,const F&f){T r=-1,m;while(l<=h){m=(l+h)/2;if(f(m)){h=m-1;r=m;}else{l=m+1;}}return r;}
template<typename T> T gcd(T a,T b) { if (a<b) swap(a,b); return b?gcd(b,a%b):a; }

template<typename T>class vector2:public vector<vector<T>>{public:vector2(){} vector2(size_t a,size_t b,T t=T()):vector<vector<T>>(a,vector<T>(b,t)){}};
template<typename T>class vector3:public vector<vector<vector<T>>>{public:vector3(){} vector3(size_t a,size_t b,size_t c,T t=T()):vector<vector<vector<T>>>(a,vector<vector<T>>(b,vector<T>(c,t))){}};
template <typename T> struct bounded_priority_queue {
	inline bounded_priority_queue(ui X) : A(X), B(0) {}
	inline void push(ui L, T V) { B = max(B, L); A[L].push(V); }
	inline const T &top() const { return A[B].front(); }
	inline void pop() { A[B].pop(); while (B > 0 && A[B].empty()) --B; }
	inline bool empty() const { return A[B].empty(); }
	inline void clear() { B = 0; for (auto &a: A) a = queue<T>(); }
private:
	vector<queue<T>> A; ui B;
};


#endif
// #include "../l/mod.h"

class D {
public:
    bool color(int H, int W, int i, int j, int D, vector2<int> &C) {
        if (i == H) {
            i = 0; j++;
            if (j == W) {
                return true;
            }
        }

        for (int c = 0; c < 4; ++c) {
            bool ok = true;
            for (int d = 0; d <= D; ++d) {
                if (j-d >= 0 && i-(D-d)>=0 && C[i-(D-d)][j-d] == c) ok = false;
            }
            for (int d = 0; d < D; ++d) {
                if (j-d >=0 && i+(D-d)< H && C[i+(D-d)][j-d] == c) ok = false;
            }
            if (ok) {
                C[i][j] = c;
                if (color(H,W,i+1,j,D,C)) {
                    return true;
                }
            }
        }
        return false;
    }

    void solve(istream& cin, ostream& cout) {
        int H, W, d; cin >> H >> W >> d;

        H += 2*d;
        W += 2*d;
        vector2<int> C(H,W,4);
        if (d%2==1) {
            for (int i = 0; i < H; ++i) {
                for (int j = 0; j < W; ++j) {
                    C[i][j] = (i+j)%2;
                }
            }
        } else {
            int dd = d/2;
            int x=0,y=0;
            queue<pii> Q;
            for (int i = 0; i < H; i+=dd) {
                y = 2*(i%(2*d)/d);
                for (int j = (i%d); j < W; j+=d) {
                    C[i][j] = x+y; Q.push({i,j});
                    if (j+1<W) {
                        C[i][j+1] = x+y;
                        Q.push({i,j+1});
                    }
                    y = 2-y;
                }
                x = 1-x;
            }

            while (!Q.empty()) {
                pii q = Q.front(); Q.pop();
                int i = q.x, j = q.y;
                if (i>0 && C[i-1][j] == 4) {
                    Q.push({i-1,j});
                    C[i-1][j] = C[i][j];
                }
                if (i<H-1 && C[i+1][j] == 4) {
                    Q.push({i+1,j});
                    C[i+1][j] = C[i][j];
                }
                if (j>0 && C[i][j-1] == 4) {
                    Q.push({i,j-1});
                    C[i][j-1] = C[i][j];
                }
                if (j<W-1 && C[i][j+1] == 4) {
                    Q.push({i,j+1});
                    C[i][j+1] = C[i][j];
                }
            }
        }

        for (int i = d; i < H - d; ++i) {
            for (int j = d; j < W - d; ++j) {
                cout << "YRGBz"[C[i][j]];
            }
            cout << '\n';
        }
    }
};


int main() {
	ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
	D solver;
	std::istream& in(std::cin);
	std::ostream& out(std::cout);
	solver.solve(in, out);
    return 0;
}


Measured memory_bytes: 25012