#include <iostream>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <algorithm>
#include <set>
#include <map>
#include <bitset>
#include <cmath>
#include <functional>
#include <iomanip>
#define vll vector<ll>
#define vvvl vector<vvl>
#define vvl vector<vector<ll>>
#define VV(a, b, c, d) vector<vector<d>>(a, vector<d>(b, c))
#define VVV(a, b, c, d) vector<vvl>(a, vvl(b, vll (c, d)));
#define re(c, b) for(ll c=0;c<b;c++)
#define rep(a,b,c) for(ll a=b;a<c;a++)
#define all(obj) (obj).begin(), (obj).end()
typedef long long int ll;
typedef long double ld;
using namespace std;

void get(vll &a){re(i,a.size()) scanf("%lld",&a[i]);}
void get(vvl &a){re(i,a.size()) re(j,a[0].size()) scanf("%lld",&a[i][j]);}
void print(vll &a){re(i,a.size()) cout<<a[i]<<(i==a.size()-1?"\n":" ");}
void print(vvl &a){re(i,a.size()) re(j,a[0].size())cout<<a[i][j]<<(j==a[0].size()-1?"\n":" ");}

int main(int argc, char const *argv[]) {
  ll a, b, c;std::cin >> a >> b >> c;
  ll ans = min({a, b, c});
  a-=ans, b-=ans, c-=ans;
  ll l = 0, r = 10000000000;
  while(r-l>1){
    //l ok r ng
    ll mid = (l+r)/2;
    ll stock = 0;
    if(a>mid) stock += (a-mid)/2;
    else stock -= (mid - a);

    if(b>mid) stock += (b-mid)/2;
    else stock -= (mid - b);

    if(c>mid) stock += (c-mid)/2;
    else stock -= (mid - c);

    if(stock>=0) l = mid;
    else r = mid;
  }
  std::cout << ans + l << '\n';
}