from collections import Counter

def gameOfThrones(s):     
    # Write your code here
    counts_s = Counter(s)

    vals = counts_s.values()

    uneven_count = 0
    for ii in vals:
        if ii % 2 != 0:
            uneven_count +=1 

    if uneven_count > 1:
        return "NO"
    else:
        return "YES"