def can_convert_to_same(D):
    # Count the number of '0's and '1's
    count_0 = D.count('0')
    count_1 = D.count('1')
    
    # Check if there is exactly one '0' or one '1'
    if count_0 == 1 or count_1 == 1:
        return "YES"
    else:
        return "NO"

# Input: Read the binary number from the user
D = input("Enter the binary number: ").strip()

# Output: Print 'YES' or 'NO' depending on the condition
print(can_convert_to_same(D))