#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <deque>
#include <iostream>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>

#define p(s) cout<<(s)<<endl
#define REP(i,n,N) for(int i=n;i<N;i++)
#define RREP(i,n,N) for(int i=N-1;i>=n;i--)
#define CK(n,a,b) ((a)<=(n)&&(n)<(b))
#define F first
#define S second
typedef long long ll;
using namespace std;
const int inf=1e9+7;

int a[3];
bool C(int n){
    int cnt=0;
    int lack=0;
    REP(i,0,3) {
        if (a[i] >= n) cnt += (a[i] - n) / 2;
        else lack += (n-a[i]);
    }
    return cnt >= lack;
}
int main(){
    cin>>a[0]>>a[1]>>a[2];
    int l=0,r=inf;
    while(r-l>1){
        int mid = (r+l)/2;
        if(C(mid)){
            l = mid;
        }else{
            r = mid;
        }
    }
    p(l);
    return 0;
}