using System;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Numerics;
using System.Runtime.CompilerServices;
using System.Text;
using System.Threading;
using static CpLibrary.StaticItems;
namespace CpLibrary.Contest
{
	public class SolverB : SolverBase
	{
		Scanner sr;
		bool hasMultipleTestcases = false;

		bool IsLocal { get; set; }

		public override void Solve()
		{
			var (n, k) = sr.ReadValue<int, int>();
			var (a, c) = sr.ReadValueArray<int, char>(k);
			var color = CreateArray(n, i => 'A');
			for (int i = 0; i < k; i++)
			{
				color[a[i] - 1] = c[i];
			}
			var ans = new StringBuilder();
			for (var i = 0; i < n; i += 3)
			{
				var left = 7;
				for (int j = 0; j < 3; j++)
				{
					if (i + j >= n) break;
					var x = GetNumCode(color[i + j]);
					if (x != 3)
					{
						if ((left & (1 << x)) != 0)
						{
							left -= 1 << x;
							ans.Append(GetCharFromCode(x));
						}
						else
						{
							var code = GetMinBit(left);
							left -= 1 << code;
							ans.Append(GetCharFromCode(code));
						}
					}
					else
					{
						var code = GetMinBit(left);
						left -= 1 << code;
						ans.Append(GetCharFromCode(code));
					}
				}
			}
			Console.WriteLine(ans.ToString());
		}

		public int GetMinBit(int n)
		{
			for (int i = 0; i < 32; i++)
			{
				if ((n & (1 << i)) != 0) return i;
			}
			return -1;
		}

		public int GetNumCode(char c)
		{
			if (c == 'R') return 0;
			else if (c == 'G') return 1;
			else if (c == 'B') return 2;
			else return 3;
		}

		public char GetCharFromCode(int x)
		{
			char[] c = { 'R', 'G', 'B', 'A' };
			return c[x];
		}

		public void Init()
		{
			/*
			 * Write your init code here if you need!
			 */
		}

		public SolverB(Scanner sr, bool isLocal = false) { this.sr = sr; this.IsLocal = isLocal; }

		public override void Run()
		{
			Init();
			var _t = 1;
			if (hasMultipleTestcases) _t = sr.ReadInt();
			while (_t-- > 0) Solve();
		}
	}

	public static class ProgramB
	{
		private static bool StartsOnThread = true;

		public static void Main(string[] args)
		{
			var sw = new StreamWriter(Console.OpenStandardOutput()) { AutoFlush = false };
			Console.SetOut(sw);
			var sr = new Scanner(new StreamReader(Console.OpenStandardInput()));
			var solver = new SolverB(sr);
			if (StartsOnThread)
			{
				var thread = new Thread(new ThreadStart(() => solver.Run()), 1 << 27);
				thread.Start();
				thread.Join();
			}
			else solver.Run();
			Console.Out.Flush();
		}

		public static void Expand() => SourceExpander.Expander.Expand();
	}
}
#region Expanded by https://github.com/naminodarie/SourceExpander
namespace CpLibrary { public static partial class StaticItems { [MethodImpl(MethodImplOptions.AggressiveInlining)] public static int PopCount(uint n) { n = (n & 0x55555555) + (n >> 1 & 0x55555555); n = (n & 0x33333333) + (n >> 2 & 0x33333333); n = (n & 0x0f0f0f0f) + (n >> 4 & 0x0f0f0f0f); n = (n & 0x00ff00ff) + (n >> 8 & 0x00ff00ff); n = (n & 0x0000ffff) + (n >> 16 & 0x0000ffff); return (int)n; }  [MethodImpl(MethodImplOptions.AggressiveInlining)] public static int PopCount(int n) => PopCount((uint)n); [MethodImpl(MethodImplOptions.AggressiveInlining)] public static int PopCount(ulong n) { n = (n & 0x5555555555555555) + (n >> 1 & 0x5555555555555555); n = (n & 0x3333333333333333) + (n >> 2 & 0x3333333333333333); n = (n & 0x0f0f0f0f0f0f0f0f) + (n >> 4 & 0x0f0f0f0f0f0f0f0f); n = (n & 0x00ff00ff00ff00ff) + (n >> 8 & 0x00ff00ff00ff00ff); n = (n & 0x0000ffff0000ffff) + (n >> 16 & 0x0000ffff0000ffff); n = (n & 0x00000000ffffffff) + (n >> 32 & 0x00000000ffffffff); return (int)n; }  [MethodImpl(MethodImplOptions.AggressiveInlining)] public static int PopCount(long n) => PopCount((ulong)n); } }
namespace CpLibrary { public static partial class StaticItems { public static int[] dx4 => new int[]{1, 0, -1, 0}; public static int[] dy4 => new int[]{0, 1, 0, -1}; public static int[] dx8 => new int[]{1, 1, 0, -1, -1, -1, 0, 1}; public static int[] dy8 => new int[]{0, 1, 1, 1, 0, -1, -1, -1}; public static bool YesNo(bool condition) { Console.WriteLine(condition ? "Yes" : "No"); return condition; }  public static bool YESNO(bool condition) { Console.WriteLine(condition ? "YES" : "NO"); return condition; }  public static bool yesno(bool condition) { Console.WriteLine(condition ? "yes" : "no"); return condition; }  public static T SignOutput<T>(int x, T pos, T zero, T neg) => x == 0 ? zero : (x > 0 ? pos : neg); public static T SignOutput<T>(long x, T pos, T zero, T neg) => x == 0 ? zero : (x > 0 ? pos : neg); public static T SignOutput<T>(double x, T pos, T zero, T neg) => x == 0 ? zero : (x > 0 ? pos : neg); public static T[] CreateArray<T>(int n, Func<int, T> func) => Enumerable.Range(0, n).Select(p => func(p)).ToArray(); public static T[][] CreateArray<T>(int x, int y, Func<int, int, T> func) => Enumerable.Range(0, x).Select(i => Enumerable.Range(0, y).Select(j => func(i, j)).ToArray()).ToArray(); public static T[][][] CreateArray<T>(int x, int y, int z, Func<int, int, int, T> func) => Enumerable.Range(0, x).Select(i => Enumerable.Range(0, y).Select(j => Enumerable.Range(0, z).Select(k => func(i, j, k)).ToArray()).ToArray()).ToArray(); } }
namespace CpLibrary { public class Scanner { public StreamReader sr { get; private set; }  string[] str; int index; char[] separators; public Scanner(StreamReader sr, char[] separators) { this.sr = sr; this.separators = separators; str = new string[0]; index = 0; }  public Scanner(StreamReader sr) : this(sr, new char[]{' '}) { }  public Scanner() : this(new StreamReader(Console.OpenStandardInput()), new char[]{' '}) { }  public string Read() { if (index < str.Length) return str[index++]; string s; do s = sr.ReadLine(); while (s == ""); str = s.Split(separators, StringSplitOptions.RemoveEmptyEntries); index = 0; return str[index++]; }  public string ReadString() => Read(); public string[] ReadStringArray(int n) { var arr = new string[n]; for (int i = 0; i < n; i++) { arr[i] = ReadString(); }  return arr; }  public int ReadInt() => int.Parse(ReadString()); public int[] ReadIntArray(int n) => ReadValueArray<int>(n); public long ReadLong() => long.Parse(ReadString()); public long[] ReadLongArray(int n) => ReadValueArray<long>(n); public double ReadDouble() => double.Parse(ReadString()); public double[] ReadDoubleArray(int n) => ReadValueArray<double>(n); public BigInteger ReadBigInteger() => BigInteger.Parse(ReadString()); public T1 ReadValue<T1>() => (T1)Convert.ChangeType(ReadString(), typeof(T1)); public (T1, T2) ReadValue<T1, T2>() => (ReadValue<T1>(), ReadValue<T2>()); public (T1, T2, T3) ReadValue<T1, T2, T3>() => (ReadValue<T1>(), ReadValue<T2>(), ReadValue<T3>()); public (T1, T2, T3, T4) ReadValue<T1, T2, T3, T4>() => (ReadValue<T1>(), ReadValue<T2>(), ReadValue<T3>(), ReadValue<T4>()); public (T1, T2, T3, T4, T5) ReadValue<T1, T2, T3, T4, T5>() => (ReadValue<T1>(), ReadValue<T2>(), ReadValue<T3>(), ReadValue<T4>(), ReadValue<T5>()); public (T1, T2, T3, T4, T5, T6) ReadValue<T1, T2, T3, T4, T5, T6>() => (ReadValue<T1>(), ReadValue<T2>(), ReadValue<T3>(), ReadValue<T4>(), ReadValue<T5>(), ReadValue<T6>()); public (T1, T2, T3, T4, T5, T6, T7) ReadValue<T1, T2, T3, T4, T5, T6, T7>() => (ReadValue<T1>(), ReadValue<T2>(), ReadValue<T3>(), ReadValue<T4>(), ReadValue<T5>(), ReadValue<T6>(), ReadValue<T7>()); public T1[] ReadValueArray<T1>(int n) { var arr = new T1[n]; for (int i = 0; i < n; i++) { arr[i] = ReadValue<T1>(); }  return arr; }  public (T1[], T2[]) ReadValueArray<T1, T2>(int n) { var(v1, v2) = (new T1[n], new T2[n]); for (int i = 0; i < n; i++) { (v1[i], v2[i]) = ReadValue<T1, T2>(); }  return (v1, v2); }  public (T1[], T2[], T3[]) ReadValueArray<T1, T2, T3>(int n) { var(v1, v2, v3) = (new T1[n], new T2[n], new T3[n]); for (int i = 0; i < n; i++) { (v1[i], v2[i], v3[i]) = ReadValue<T1, T2, T3>(); }  return (v1, v2, v3); }  public (T1[], T2[], T3[], T4[]) ReadValueArray<T1, T2, T3, T4>(int n) { var(v1, v2, v3, v4) = (new T1[n], new T2[n], new T3[n], new T4[n]); for (int i = 0; i < n; i++) { (v1[i], v2[i], v3[i], v4[i]) = ReadValue<T1, T2, T3, T4>(); }  return (v1, v2, v3, v4); }  public (T1[], T2[], T3[], T4[], T5[]) ReadValueArray<T1, T2, T3, T4, T5>(int n) { var(v1, v2, v3, v4, v5) = (new T1[n], new T2[n], new T3[n], new T4[n], new T5[n]); for (int i = 0; i < n; i++) { (v1[i], v2[i], v3[i], v4[i], v5[i]) = ReadValue<T1, T2, T3, T4, T5>(); }  return (v1, v2, v3, v4, v5); }  public (T1[], T2[], T3[], T4[], T5[], T6[]) ReadValueArray<T1, T2, T3, T4, T5, T6>(int n) { var(v1, v2, v3, v4, v5, v6) = (new T1[n], new T2[n], new T3[n], new T4[n], new T5[n], new T6[n]); for (int i = 0; i < n; i++) { (v1[i], v2[i], v3[i], v4[i], v5[i], v6[i]) = ReadValue<T1, T2, T3, T4, T5, T6>(); }  return (v1, v2, v3, v4, v5, v6); }  public (T1[], T2[], T3[], T4[], T5[], T6[], T7[]) ReadValueArray<T1, T2, T3, T4, T5, T6, T7>(int n) { var(v1, v2, v3, v4, v5, v6, v7) = (new T1[n], new T2[n], new T3[n], new T4[n], new T5[n], new T6[n], new T7[n]); for (int i = 0; i < n; i++) { (v1[i], v2[i], v3[i], v4[i], v5[i], v6[i], v7[i]) = ReadValue<T1, T2, T3, T4, T5, T6, T7>(); }  return (v1, v2, v3, v4, v5, v6, v7); }  public (T1, T2)[] ReadTupleArray<T1, T2>(int n) { var ret = new (T1, T2)[n]; for (int i = 0; i < n; i++) { ret[i] = ReadValue<T1, T2>(); }  return ret; }  public (T1, T2, T3)[] ReadTupleArray<T1, T2, T3>(int n) { var ret = new (T1, T2, T3)[n]; for (int i = 0; i < n; i++) { ret[i] = ReadValue<T1, T2, T3>(); }  return ret; }  public (T1, T2, T3, T4)[] ReadTupleArray<T1, T2, T3, T4>(int n) { var ret = new (T1, T2, T3, T4)[n]; for (int i = 0; i < n; i++) { ret[i] = ReadValue<T1, T2, T3, T4>(); }  return ret; }  public (T1, T2, T3, T4, T5)[] ReadTupleArray<T1, T2, T3, T4, T5>(int n) { var ret = new (T1, T2, T3, T4, T5)[n]; for (int i = 0; i < n; i++) { ret[i] = ReadValue<T1, T2, T3, T4, T5>(); }  return ret; }  public (T1, T2, T3, T4, T5, T6)[] ReadTupleArray<T1, T2, T3, T4, T5, T6>(int n) { var ret = new (T1, T2, T3, T4, T5, T6)[n]; for (int i = 0; i < n; i++) { ret[i] = ReadValue<T1, T2, T3, T4, T5, T6>(); }  return ret; }  public (T1, T2, T3, T4, T5, T6, T7)[] ReadTupleArray<T1, T2, T3, T4, T5, T6, T7>(int n) { var ret = new (T1, T2, T3, T4, T5, T6, T7)[n]; for (int i = 0; i < n; i++) { ret[i] = ReadValue<T1, T2, T3, T4, T5, T6, T7>(); }  return ret; } } }
namespace CpLibrary { public interface ISolver { public void Solve(); public void Run(); }  public abstract class SolverBase : ISolver { public abstract void Solve(); public abstract void Run(); } }
namespace SourceExpander{public class Expander{[Conditional("EXP")]public static void Expand(string inputFilePath=null,string outputFilePath=null,bool ignoreAnyError=true){}public static string ExpandString(string inputFilePath=null,bool ignoreAnyError=true){return "";}}}
#endregion Expanded by https://github.com/naminodarie/SourceExpander