#include<bits/stdc++.h>
#include<math.h>
using namespace std;
using ll = long long;
#define rep(i,n) for (int i=0; i<(n);++i)

int main(){
    int N = 3;
    vector<int> A(N);
    rep(i,N) cin >> A[i];
    sort(A.begin(), A.end());
    if((A[2]-A[1])==A[1]-A[0]) cout << "Yes" << endl;
    else cout << "No" << endl;
}
#include <bits/stdc++.h>

using namespace std;

int main() {

  int A1,A2,A3;

  cin>>A1>>A2>>A3;

  if((max(A1,max(A2,A3))-max(A1,min(A2,A3)))==(max(A1,min(A2,A3))-min(A1,min(A2,A3))))

{cout<<"Yes"<<endl;}

  else if((max(A1,max(A2,A3))-min(A1,max(A2,A3)))==(min(A1,max(A2,A3))-min(A1,min(A2,A3))))

{cout<<"Yes"<<endl;}

  

  else{cout<<"No"<<endl;}

}