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

bool can_create(int k,int r,int g,int b){
    r -= k;
    g -= k;
    b -= k;
    int plus = 0;
    int minus = 0;
    if(r > 0){
        plus += r;
    } else {
        minus -= r;
    }
    if(g > 0){
        plus += g;
    } else {
        minus -= g;
    }
    if(b > 0){
        plus += b;
    } else {
        minus -= b;
    }
    if(plus >= minus * 2){
        return true;
    }
    return false;
}

int main(){
    int i,r,g,b;
    scanf("%d %d %d",&r,&g,&b);
    int left = 0,right = r+g+b;
    int mid;
    while(right - left > 2){
        mid = (right + left)/2;
        if(can_create(mid,r,g,b)){
            left = mid;
        } else {
            right = mid;
        }
    }
    printf("%d",left);
}