#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int main() {
    int nums[9];
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    for(int i = 0; i < 9; i++)
    {
        scanf("%d", &nums[i]);
    }
    int cost = 0;
    int repeat;
    int indexNums[9];
    int missing;
    for(int i = 0; i < 9; i++)
    {
        indexNums[i] = 0;   
    }
    for(int i = 0; i < 9; i++)
    {
        indexNums[nums[i]] += 1;   
    }
    for(int i = 0; i < 9; i++)
    {
        if(indexNums[i] == 2)
        {
            repeat = i + 1;
        }
        if(indexNums[i] == 0)
        {
            missing = i + 1;
        }
    }
    cost = abs(repeat - missing);
    printf("%d", cost);
    return 0;
}