//No.154 市バス import java.util.*; import java.io.*; import static java.util.Arrays.*; import static java.lang.Math.*; public class No154 { static final InputStream in = System.in; static final PrintWriter out = new PrintWriter(System.out,false); static void solve(){ int t = nextInt(); while (t-- > 0) { char[] cs = next().toCharArray(); out.println((check(cs) && check2(cs)) ? "possible" : "impossible"); } } static boolean check(char[] cs) { int n = cs.length; int[] wgr = new int[3]; for (int i=0; i=0; i--) { if (cs[i] == 'X') {cnt++; continue;} if (cs[i] == 'R') { if (!wgr[2]) { wgr[2] = true; cs[i] = 'X'; } }else { if (!wgr[2]) return false; if (cs[i] == 'G') { if (!wgr[1]) { wgr[1] = true; cs[i] = 'X'; }else if (wgr[0]) { break; } }else { if (!wgr[1] || !wgr[1]) return false; wgr[0] = true; cs[i] = 'X'; } } } if (cnt == n) return true; if (!wgr[0] || !wgr[1] || !wgr[2]) return false; return check2(cs); } public static void main(String[] args) throws Exception { long start = System.currentTimeMillis(); solve(); out.flush(); long end = System.currentTimeMillis(); //trace(end-start + "ms"); in.close(); } static void trace(Object... o) { System.out.println(deepToString(o));} static final byte[] buf = new byte[1024]; static int ptr = 0; static int buflen = 0; static boolean hasNextByte() { if (ptr < buflen) return true; ptr = 0; try{ buflen = in.read(buf); }catch (IOException e) {e.printStackTrace();} if (buflen <= 0) return false; return true; } static int readByte() { if (hasNextByte()) return buf[ptr++]; else return -1;} static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;} static void skip() { while(hasNextByte() && !isPrintableChar(buf[ptr])) ptr++;} static boolean hasNext() {skip(); return hasNextByte();} static String next() { if (!hasNext()) throw new NoSuchElementException(); StringBuilder sb = new StringBuilder(); int b = readByte(); while (isPrintableChar(b)) { sb.appendCodePoint(b); b = readByte(); } return sb.toString(); } static long nextLong() { if (!hasNext()) throw new NoSuchElementException(); boolean minus = false; long num = readByte(); if(num == '-'){ num = 0; minus = true; }else if (num < '0' || '9' < num){ throw new NumberFormatException(); }else{ num -= '0'; } while(true){ int b = readByte(); if('0' <= b && b <= '9') num = num * 10 + (b - '0'); else if(b == -1 || !isPrintableChar(b)) return minus ? -num : num; else throw new NoSuchElementException(); } } static int nextInt() { long num = nextLong(); if (num < Integer.MIN_VALUE || Integer.MAX_VALUE < num) throw new NumberFormatException(); return (int)num; } static double nextDouble() { return Double.parseDouble(next()); } static char nextChar() { if (!hasNext()) throw new NoSuchElementException(); return (char)readByte(); } static String nextLine() { while (hasNextByte() && (buf[ptr] == '\n' || buf[ptr] == '\r')) ptr++; if (!hasNextByte()) throw new NoSuchElementException(); StringBuilder sb = new StringBuilder(); int b = readByte(); while (b != '\n' && b != '\r') { sb.appendCodePoint(b); b = readByte(); } return sb.toString(); } static int[] nextArrayInt(int n) { int[] a = new int[n]; for (int i=0; i