from collections import Counter
def happyLadybugs(b):
    # Write your code here
    if len(b) == 1 and b[0] == '_':
        return 'YES'
    if len(b) == 1 and b[0] != '_':
        return 'NO'
    c = Counter(b)
    flag = 0
    if c['_'] == 0:
        for i in range(len(b)):
            if i == 0:
                if b[i] == b[i+1]:
                    continue
                else:
                    flag+=1
            if i == len(b)-1:
                if b[i] == b[i-1]:
                    continue
                else:
                    flag+=1
            if i > 0 and i < len(b)-1:
                if b[i] == b[i-1] or b[i] == b[i+1]:
                    continue
                else:
                    flag+=1
                    
    for m, n in c.items():
        if n <= 1 and m != '_':
            return 'NO'
            
    return 'YES' if not flag else 'NO'