#include <stdio.h>
int main(void){
    int x,y,z;
    scanf("%d %d %d",&x,&y,&z);
    for(;z>1;){
        if(x>y){
            y++;
            z--;
        }
        else if(y<x){
            z--;
            x++;
        }
        else if(x==y&&z>=2){
            z=z-2;
            x++;
            y++;
        }
        else if(z<=1){break;}
        
    }
    
    printf("%d\n",x);
    return 0;
}