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

#define FOR(i, m, n) for(int (i) = (m); (i) < (n); (i)++)
#define FORN(i, m, n) for(int (i) = (m); (i) <= (n); (i)++)
#define FORR(i, m, n) for(int (i) = (m); (i) >= (n); (i)--)
#define rep(i, n) FOR(i, 0, n)
#define repn(i, n) FORN(i, 1, n)
#define repr(i, n) FORR(i, n, 0)
#define repnr(i, n) FORR(i, n, 1)
#define co(n) cout << (n) << endl
#define cosp(n) cout << (n) << ' '
#define setp(n) cout << fixed << setprecision(n);
#define all(s) (s).begin(), (s).end()
#define pb push_back
#define mp make_pair
#define fs first
#define sc second
typedef long long ll;
typedef pair<int, int> P;

const ll INF = 1e9+1;
const ll LINF = 1e18+1;
const ll MOD = 1e9+7;
//const ll MOD = 998244353;
const double PI = acos(-1);
const double EPS = 1e-9;

int main(void){
	int x, y, z;
	cin >> x >> y >> z;
	if(x+z < y) co(x+z);
	else if(y+z < x) co(y+z);
	else co((x+y+z)/2);

	return 0;
}