#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
#define ll long long
#define pp pair<ll,ll>
#define ld long double
#define all(a) (a).begin(),(a).end()
#define mk make_pair
int inf=1000001000;
ll INF=2e18;
ll mod=1000000007;
ll MOD=998244353;

int main() {
   vector<int> a(4);
   rep(i,4) cin >> a[i];
   bool t=false;
   rep(j,16){
    int b=0,c=0;
     int f=j;
     rep(i,4){
       if (f%2==0) b+=a[i];
       else c+=a[i];
       f/=2;
     }
     if (b==c) t=true;
   }
   if (t) cout << "Yes" << endl;
   else cout << "No" << endl;
}

#include <bits/stdc++.h>
#define pb push_back
#define mp make_pair
#define f first
#define s second
#define ll long long int

using namespace std;

typedef vector<int> vi;
typedef pair<int,int> ii;
typedef vector<ii> vii;

int main(){
    int n, k, m ;
    scanf("%d %d %d", &n, &k, &m);
    vi v(n-1);
    int sum = 0;
    for(int i = 0; i < n-1; i++){
        scanf("%d", &v[i]);
        sum += v[i];
    }
    int r = -1;
    for(int i = 0; i <= k; i++){
        if((sum+i)/n >= m){
            r = i;
            break;
        }
    }  
    printf("%d\n", r);
    return 0;
}