import sys

a = list(map(int, input().split()))
n = len(a)
def nand(x, y):
  return 0 if x == 1 and y == 1 else 1
for b in range(1 << n):
  c = [1 if (b & (1 << i)) else 0 for i in range(n)]
  ok = True
  for i in range(n):
    for j in range(i + 1, n):
      if c[i] != c[j] and a[i] == a[j]:
        ok = False
        break
  if not ok:
    continue
  if nand(nand(nand(c[0], c[1]), c[2]), nand(nand(c[3], c[4]), c[5])):
    print("YES")
    sys.exit()
print("NO")