44 58 90 53
 20 14 37 71
 4 2 4 2
 1 2 5 5
 1 2 8 9
 99 100 3 98
 92 69 83 97
 3 1 1 1
 18 88 18 18
 1 1 1 1
 69 7 44 30
 90 30 30 30
 1 2 3 5
 1 1 3 1
 6 3 6 6
 26 52 7 19
 6 4 8 6
 10 2 3 5
 34 11 84 39
 1 1 14 12
 3 2 1 1
 2 4 6 6
 1 1 2 1
 72 96 2 26
 97 95 91 27
 1 2 1 3
 1 1 2 3
 1 1 1 2
 1 1 10 20
 2 3 2 5
 1 2 10 7
 2 1 28 9
 4 4 4 8
 2 2 4 6
 72 52 62 62
 76 97 99 74
 100 100 99 100
 30 74 41 63
 5 10 1 6
 18 17 17 20
 2 4 1 1
 7 3 6 3
 1 1 4 5
 2 2 6 2
 1 2 6 3
 3 5 1 3
 70 100 10 86
 48 14 3 31
 2 6 3 2
 2 3 10 10
 4 4 12 4
 14 9 10 6
 100 98 99 97
 5 7 1 3
 1 1 4 2
 14 10 18 24
 1 100 100 1
 1 2 4 5
 1 2 3 4
 1 2 3 3
 4 4 4 5
 66 68 16 82
 1 2 3 2
 2 3 3 4
 100 100 100 100
 1 2 2 7
 3 14 36 53
 1 1 3 4

NO
 YES
 YES
 NO
 YES
 NO
 NO
 YES
 NO
 YES
 NO
 YES
 NO
 YES
 NO
 YES
 YES
 YES
 YES
 YES
 NO
 NO
 NO
 YES
 NO
 NO
 NO
 NO
 NO
 NO
 YES
 NO
 NO
 NO
 YES
 YES
 NO
 YES
 YES
 NO
 YES
 NO
 NO
 YES
 YES
 YES
 NO
 YES
 NO
 NO
 YES
 NO
 YES
 YES
 YES
 NO
 YES
 YES
 YES
 NO
 NO
 NO
 YES
 YES
 YES
 NO
 YES
 NO

# filename: 1230A-Dawidandbagsofcandies

# problem definition: brute force, implementation *800

# input string
bags_raw = raw_input() # numbers 1 <= n <= 100

# fake input
# bags_raw = "0 0 1 5"

# const
NO_BAGS = 4

# initialize
bags = []
bags_raw = bags_raw.split()
total_candies = 0
for i in range(0,NO_BAGS):
    bags.append(int(bags_raw[i]))
    total_candies = total_candies + int(bags_raw[i]) 

equal_candies_flag = 0

# algorithm
if total_candies % 2 == 0 :
    half_candies = total_candies / 2
    equal_candies_flag = 0
    for i in range(0,NO_BAGS-1):
        for j in range(i,NO_BAGS):
            if bags[i] + bags[j] ==  half_candies :
                equal_candies_flag = 1; 

    # print result
    if equal_candies_flag == 1:
        print("YES")
    else :
        print("NO")

else :
    # print result
    print("NO")
    


# 