S = input().strip()

n = len(S)
found = False

for start in range(n):
    for end in range(start, n):
        length = end - start + 1
        if length % 2 != 0 or length < 2:
            continue
        
        valid = True
        ev_letters = set()
        for i in range(0, length, 2):
            pos = start + i
            if pos >= n or S[pos] == ' ':
                valid = False
                break
            ev_letters.add(S[pos])
        if not valid:
            continue
        
        R = set()
        for i in range(1, length, 2):
            pos = start + i
            if pos >= n:
                valid = False
                break
            if S[pos] != ' ':
                R.add(S[pos])
        if not valid:
            continue
        
        for i in range(n):
            if i < start or i > end:
                if S[i] != ' ':
                    R.add(S[i])
        
        if ev_letters.isdisjoint(R):
            found = True
            break
    if found:
        break

print("Yes" if found else "No")