import java.util.Arrays;
import java.util.Scanner;


public class Main_yukicoder91 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int[] rgb = new int[3];
        for (int i = 0; i < 3; i++) {
        	rgb[i] = sc.nextInt();
        }
        Arrays.sort(rgb);

        int l = 0;
        int r = 10_000_001;
		while (r > l) {
        	int mid = (r + l) / 2;
        	int value = 0;
        	int value2 = 0;
        	for (int i = 0; i < 3; i++) {
        		if (rgb[i] >= 10_000_000 - mid) {
        			int tmp = rgb[i] - (10_000_000 - mid);
        			if (tmp > 1) {
        				value += tmp;
        			}
        		} else {
        			value2 += (10_000_000 - mid) - rgb[i];
        		}
        	}
        	if (value >= value2 * 2) {
        		r = mid;
        	} else {
        		l = mid + 1;
        	}
        }

        System.out.println(10_000_000 - r);

        sc.close();
    }
}