ارسال شماره 953

a,b,c,d = map(int,input().split())

if a == b and b == c and c == d:
    print("NO")
    
elif a == b and c == d:
    print("YES")

elif a == c and b == d:
    print("YES")

elif a == d and b == c:
    print("YES")

else:
    print("NO")