import sys

def debug(x, table):
    for name, val in table.items():
        if x is val:
            print('DEBUG: {} -> {}'.format(name, val), file=sys.stderr)
            return None

n, a = map(int, input().split())

x = [int(i) for i in input().split()]
ave = sum(x) / n

if a == ave:
    ans = 'YES'
else:
    ans = 'NO'

print(ans)