#include <bits/stdc++.h>
#define REP(i,n) for(ll i=0;i<(ll)(n);i++)
#define REPD(i,n) for(ll i=n-1;i>=0;i--)
#define FOR(i,a,b) for(ll i=a;i<=(ll)(b);i++)
#define FORD(i,a,b) for(ll i=a;i>=(ll)(b);i--)
#define ALL(x) (x).begin(),(x).end()
#define RALL(x) (x).rbegin(),(x).rend()
#define SIZE(x) ((ll)(x).size())
#define MAX(x) *max_element(ALL(x))
#define MIN(x) *min_element(ALL(x))
using namespace std;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
typedef long long ll;
const int INF = INT32_MAX;
using P = pair<int, int>;

int main() {
    int a, b, c;
    cin >> a >> b >> c;

    if(a + b == 2 * c){
        cout << "Yes" << endl;
        return 0;
    }
    if(a + c == 2 * b){
        cout << "Yes" << endl;
        return 0;
    }
    if(c + b == 2 * a){
        cout << "Yes" << endl;
        return 0;
    }
    
    cout << "No" << endl;

    return 0;
}
#include <bits/stdc++.h>
using namespace std;

int main() {

    int a,b,c;
    cin >> a >> b >> c;

    if(a > b) swap(a,b);
    if(a>c) swap(a,c);
    if(b>c) swap(b,c);

    if(b-a == c-b) cout << "Yes";
    else cout << "No";


    return 0;
}