#include<cstdio>
#include<cstdlib>
#include<algorithm>

int main(){
    int x, y, z;
    scanf("%d %d %d", &x, &y, &z);

    int a = abs(x-y), ans = std::min(x, y);
    if(a<=z){
        ans += a;
        z -= a;
        a = 0;
    }else{
        ans += z;
        a -= z;
        z = 0;
    }
    ans += z/2;
    printf("%d\n", ans);
    return 0;
}