def isBalanced(s):
    # Valid combos that must exist as pairs
    combos = ["[]", "{}", "()"]
    
    # While there are characters available, attempt to remove combos
    while len(s) > 0:
        new_s = s
        for c in combos:
            new_s = new_s.replace(c, "")
        # If the new_s has not changed length (ie no valid combos) return NO
        if len(new_s) == len(s):
            return "NO"
        s = new_s
    return "YES"