#int(input())
#map(int, input().split())
#list(map(int, input().split()))

def NAND(a, b):
    return -(a & b) + 1

def f(x):
    return NAND(NAND(NAND(x[0], x[1]), x[2]), NAND(NAND(x[3], x[4]), x[5]))

A = list(input().split())

a = [0] * 6
for i in range(6):
    a[i] = A.index(A[i])

ans = 0

for i in range(1 << 6):
    b = format(i, "06b")
    u = [0] * 6
    for j in range(6):
        u[j] = int(b[a[j]])
    if f(u):
        ans = 1
        break

if ans == 1:
    print("YES")
else:
    print("NO")