#include <stdio.h>

int main(void) {
	int t;
	char s[1001];
	int i, j;
	int g;
	int possible;
	scanf("%d", &t);
	for(i = 0;i < t;i++){
		scanf("%s", s);
		possible = 1;
		g = 0;
		j = 0;
		while(s[j] != '\0'){
			if(s[j] == 'R'){
				if(g == 0){
					possible = 0;
					break;
				}
				else{
					g--;
				}
			}
			else if(s[j] == 'G'){
				g++;
			}
			j++;
		}
		if(possible == 1 && g == 0){
			printf("possible\n");
		}
		else{
			printf("impossible\n");
		}
	}

	return 0;
}