// yukicoder: No.154 市バス
// 2019.5.10 bal4u

#include <stdio.h>

#if 1
#define gc() getchar_unlocked()
#define pc(c) putchar_unlocked(c)
#else
#define gc() getchar()
#define pc(c) putchar(c)
#endif
int in()    // 非負整数の入力
{
	int n = 0, c = gc();
	//	while (isspace(c)) c = gc();
	do n = 10 * n + (c & 0xf), c = gc(); while (c >= '0');
	return n;
}

int ins(char *s)  // 文字列の入力　スペース以下の文字で入力終了
{
	char *p = s;
	do *s = gc();
	while (*s++ > ' ');
	*--s = 0;
	return s - p;
}

void outs(char *s) { while (*s) pc(*s++); }

char S[1005];
int q[3][1005], sz[3];
int id[128];

int main()
{
	int i, j, k, T, len;
	
	id['W'] = 0, id['G'] = 1, id['R'] = 2;
	T = in(); while (T--) {
		sz[0] = sz[1] = sz[2] = 0;
		len = ins(S);
		if (*(S+len-1) != 'R') goto NG;
		for (i = 0; i < len; i++)
			j = id[S[i]], q[j][sz[j]++] = i;
		if (sz[0] < sz[1] || sz[1] != sz[2]) goto NG;
		k = 0; for (j = 0; j < sz[1]; j++) {
			while (q[2][k] < q[1][j]) k++;
			if (k > j) goto NG;
		}
		i = sz[0]-1; for (j = sz[1]-1; j >= 0; j--) {
			while (q[0][i] > q[1][j]) i--;
			if (sz[0]-i > sz[1]-j) goto NG;
		}
		outs("possible\n");
		continue;
NG:		outs("impossible\n");
	}
	return 0;
}