def is_possible(s):
    g_count = s.count('G')
    r_count = s.count('R')
    if g_count != r_count:
        return False
    w_count = s.count('W')
    if w_count < g_count:
        return False
    
    # Check each G has at least one W before it
    n = len(s)
    prefix_w = [0] * (n + 1)
    for i in range(n):
        prefix_w[i+1] = prefix_w[i] + (1 if s[i] == 'W' else 0)
    for i in range(n):
        if s[i] == 'G' and prefix_w[i] == 0:
            return False
    
    # Check R count never exceeds G count during processing
    current_g = 0
    current_r = 0
    for c in s:
        if c == 'G':
            current_g += 1
        elif c == 'R':
            current_r += 1
        if current_r > current_g:
            return False
    return True

T = int(input())
for _ in range(T):
    S = input().strip()
    if is_possible(S):
        print("possible")
    else:
        print("impossible")