#include <stdio.h>

#define MAX0(x) ((x) > 0 ? (x) : 0)

int r, g, b;


int p(int x){
  int rr = r-x;
  int rg = g-x;
  int rb = b-x;
  int s = MAX0(rr)/2 + MAX0(rg)/2 + MAX0(rb)/2;
  int c = MAX0(-rr) + MAX0(-rg) + MAX0(-rb);
  return s >= c;
}

int main(){
  int lb, ub;
  scanf("%d%d%d", &r, &g, &b);

  ub = 10000001;
  lb = 0;

  while(ub - lb > 1){
    int m = (lb + ub) / 2;
    if(p(m)) lb = m;
    else ub = m;
  }

  printf("%d\n", lb);

  return 0;
}