def is_possible(s):
    g_count = s.count('G')
    r_count = s.count('R')
    
    if g_count != r_count:
        return False
    
    # Check each G has an R after it
    for i in range(len(s)):
        if s[i] == 'G':
            found_r = False
            for j in range(i+1, len(s)):
                if s[j] == 'R':
                    found_r = True
                    break
            if not found_r:
                return False
    
    # Check Ws before each G
    for i in range(len(s)):
        if s[i] == 'G':
            # Find the last R before i
            last_r = -1
            for j in range(i-1, -1, -1):
                if s[j] == 'R':
                    last_r = j
                    break
            # Determine the start of the segment
            start = 0 if last_r == -1 else last_r + 1
            end = i - 1
            # Count Ws in this segment
            w_count = 0
            for k in range(start, end + 1):
                if s[k] == 'W':
                    w_count += 1
            if w_count < 1:
                return False
    
    return True

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