#include <bits/stdc++.h>
using namespace std;
 
int main() {
    int a,b,c;
  cin>>a;
  cin>>b;
  cin>>c;

    if(a-(2*b)+c == 0){
         cout << "Yes" << endl;
    }
      else if(a-(2*c)+b == 0){
         cout << "Yes" << endl;
    }
      else if(a-(2*b)+c == 0){
         cout << "Yes" << endl;
    }
        else if(b-(2*a)+c == 0){
         cout << "Yes" << endl;
    }
        else if(b-(2*c)+a == 0){
         cout << "Yes" << endl;
    }
          else if(c-(2*a)+b == 0){
         cout << "Yes" << endl;
    }
          else if(c-(2*b)+a == 0){
         cout << "Yes" << endl;
    }
    else{
         cout << "No" << endl;
    }
  
}
#include<bits/stdc++.h>
#define pb push_back
#define ppb pop_back
#define pf push_front
#define ppf pop_front
#define all(x) (x).begin(),(x).end()
#define sz(x) (int)((x).size())
#define fast ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define int long long
typedef unsigned long long ull;
typedef long double ld;
using namespace std;
const int INF=1e16+1;
const int mod=1000000007;
//const int mod=998244353;
int custom_ceil(int Nr,int Dr){
    if(Nr%Dr==0)return Nr/Dr;
    else return Nr/Dr+1;
}
void solve(){
    int a[3];
    cin>>a[0]>>a[1]>>a[2];
    do{
        if(a[1]-a[0]==a[2]-a[1]){
            cout<<"Yes\n";
            return;
        }
    }while(next_permutation(a,a+3));
    cout<<"No\n";
}
int32_t main(){
    fast;
    int t=1;
    //cin>>t;
    while(t--){
        solve();
    }
    return 0;
}