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

public class GetLastFruit {
    public static void log(Object obj) {
        System.out.println(obj.toString());
    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int[] a = new int[3];
        boolean[] y = new boolean[4];
        for(int i=0;i<3;i++) {
            a[i] = sc.nextInt();
            y[a[i]] = true;
        }
        Arrays.sort(a);
        if(a[1]==a[2]) {
            log(a[0]);
        } else if (a[0]==a[1]) {
            log(a[2]);
        } else {
            for(int i=0;i<4;i++) {
                if(!y[i]) {
                    log(a[i]-1);
                }
            }
        }
    }
}