a,b,c,d,e,f=map(int,input().split())
s=set([a,b,c,d,e,f])
s=list(s)
n=len(s)

def NAND(x,y):
  if x==y==1:
    return 0
  else:
    return 1

for bit in range(1<<n):
  dic={}
  for i in range(n):
    if (bit>>i)&1:
      dic[s[i]]=1
    else:
      dic[s[i]]=0
  
  if NAND(NAND(NAND(dic[a],dic[b]),dic[c]),NAND(NAND(dic[d],dic[e]),dic[f]))==1:
    print('YES')
    exit()

print('NO')