fun main() {
    val (n, k) = readInts()
    val arr = CharArray(n) { 'R' }
    for (i in 0 until k) {
        val data = readln().split(" ")
        val a = data[0].toInt()
        val c = data[1][0]
        arr[a - 1] = c
    }
    val ans = CharArray(n) { '.' }
    for (i in 0 until n) {
        val c = arr[i]
        if (i % 3 == 0) {
            ans[i] = c
        } else if (i % 3 == 1) {
            if (ans[i - 1] == c) {
                ans[i] = if (c == 'R') 'G' else 'R'
            } else {
                ans[i] = c
            }
        } else {
            val lst = mutableListOf('R', 'G', 'B')
            lst.remove(ans[i - 1])
            lst.remove(ans[i - 2])
            ans[i] = lst[0]
        }
    }
    println(ans.joinToString(""))
}

fun readInts() = readln().split(" ").map { it.toInt() }