// Equality
package Bronze_IV_4;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
public class Ex13985 {
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
StringTokenizer st = new StringTokenizer(br.readLine());
int a = Integer.parseInt(st.nextToken());
String digit = st.nextToken();
int b = Integer.parseInt(st.nextToken());
String equal = st.nextToken();
int c = Integer.parseInt(st.nextToken());
if (a + b == c) {
System.out.println("YES");
} else {
System.out.println("NO");
}
}
}