#include <iostream>
#include <vector>
#include <cmath>
using namespace std;
class Matrix {
	public:
		vector<vector<int>> a;
		
		int sum_row(int row) {
			vector<int> r = this->a[row];
			int sum = 0;
			for (int c = 0; c < r.size(); c++) {
				sum += r[c];
			}
			return sum;
		}

		int sum_col(int col) {
			int sum = 0;
			for (int r = 0; r < this->a.size(); r++) {
				vector<int> row = this->a[r];
				sum += row[col];
			}
			return sum;
		}

		int sum_main_diag() {
			int sum = 0;
			for (int i = 0; i < this->a.size(); i++) {
				sum += this->a[i][i];
			}
			return sum;
		}

		int sum_alt_diag() {
			int sum = 0;
			for (int i = 0; i < this->a.size(); i++) {
				sum += this->a[this->a.size()-i-1][i];
			}
			return sum;
		}

		Matrix &operator+=(const Matrix &rhs) {
			for (int row_index = 0; row_index < rhs.a.size(); row_index++) {
				for (int v = 0; v < rhs.a[0].size(); v++) {
					this->a[row_index][v] += rhs.a[row_index][v];
				}
			}
			return *this;
		}

		friend Matrix operator+(Matrix a, const Matrix &b) {
			a += b;
			return a;
		}
};
int main() {
	int size = 3;
	Matrix m;
	for (int i = 0; i < size; i++) {
		vector<int> b;
		int num;
		for (int j = 0; j < size; j++) {
			cin >> num;
			b.push_back(num);
		}
		m.a.push_back(b);
	}

	int a,b,c,cost;
	c = m.a[1][1];
//	cout << "c = " << c << endl;

	int A0 = c - m.a[0][2];
//	cout << "A0 = " << A0 << endl;

	int A1 = m.a[2][0] - c;
//	cout << "A1 = " << A1 << endl;
	int R0 = m.sum_row(0), R1 = m.sum_row(2);
	if (A1 != A0) {
		if (R0 == 15) {
			a = A0;
		} else {
			a = A1;
		}
		cost = abs(A1 - A0);
	}	else {
		a = A0;
	}
	
	int B0 = c - m.a[0][0],
			B1 = m.a[2][2] - c;
	if (B1 != B0) {
		if (R0 == 15) {
			b = B0;
		} else {
			b = B1;
		}	
		cost = abs(B1 - B0);
	} else {
		b = B0;
	}
	
	//cout << "a = " << a << endl;
	//cout << "b = " << b << endl;
	//cout << "c = " << c << endl;
	cout << cost << endl;
	return 0;
}