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

import java.util.Scanner;
public class test {
    public static void main(String[] args)
    {
        Scanner sc=new Scanner(System.in);
        int a1 = sc.nextInt();
        int a2 = sc.nextInt();
        int a3 = sc.nextInt();
        int a4 = sc.nextInt();

        int sum1 = a1+a2;
        int sum2 = a3+a4;

        int sum3 = a1+a3;
        int sum4 = a2+a4;

        int sum5 = a1+a4;
        int sum6 = a2+a3;

        int sum7 = a1+a2+a3;
        int sum8 = a1+a2+a4;
        int sum9 = a1+a3+a4;
        int sum10= a2+a3+a4;

        if(sum1 == sum2)
        {
            System.out.print("YES");
        }
        else if(sum3 == sum4)
        {
            System.out.print("YES");
        }

        else if(sum5 == sum6)
        {
            System.out.print("YES");
        }
        else if(sum7 == a4)
        {
            System.out.print("YES");
        }
        else if(sum8 == a3)
        {
            System.out.print("YES");
        }
        else if(sum9 == a2)
        {
            System.out.print("YES");
        }
        else if(sum10 == a1)
        {
            System.out.print("YES");
        }
        else
        {
            System.out.print("NO");
        }
    }
}

			 					 	 		   	 	 		   			