fun main(arr:Array<String>) {
    val inputCount = readLine()!!.toInt()
    (1..inputCount).map { if(isValid(readLine()!!)) "possible" else "impossible" }.forEach { println(it) }
}

fun isValid(inpt:String):Boolean {
    val log = inpt.reversed()
    val line = mutableListOf<Char>()
    for(i in log) {
        if(i == 'R') {
            line.add(i)
        } else if(i == 'G') {
            val idx = line.indexOfFirst { it == 'R' }
            if(idx < 0) {
                return false
            }
            line[idx] = 'G'
        } else if(i == 'W') {
            val idx = line.indexOfFirst { it == 'G' }
            if(idx < 0) {
                val idx2 = line.indexOfFirst { it == 'W' }
                if(idx2 < 0) {
                    return false
                } else {
                    line[idx2] = 'W'
                }
            } else {
                line[idx] = 'W'
            }
        }
    }
    return line.all { it == 'W' }
}