text = list(map(str, input()))
index = 0
flag = False
for i in text:
    if index >= len(text) - 1:
        break
    if i == text[index + 1]:
        print(i)
        print(text[index + 1])
        flag = True
        print("YES")
        break
    index += 1
    
if flag == False:
    print("NO")