from itertools import product
a = list(map(int, input().split()))
d = {x: i for i, x in enumerate(set(a))}
for i in range(6):
    a[i] = d[a[i]]

def nand(x, y):
    return not (x and y)

for p in product(range(2), repeat=len(d)):
    if nand(nand(nand(p[a[0]], p[a[1]]), p[a[2]]), nand(nand(p[a[3]], p[a[4]]), p[a[5]])):
        print('YES')
        break
else:
    print('NO')