#include<iostream>
using namespace std;

int main() {

	int input = 0;
	cin >> input;

	int** arr;
	arr = new int* [input];

	for (int i = 0; i < input; i++) {
		arr[i] = new int[3];
		for (int j = 0; j < 3; j++) {
			cin >> arr[i][j];
		}
	}

	for (int i = 0; i < input - 1; i++) {
		if (arr[i][1] > arr[i][2]) {
			arr[i + 1][0] += arr[i][2];
		}
		else {
			arr[i + 1][0] += arr[i][1];
		}
		if (arr[i][0] > arr[i][2]) {
			arr[i + 1][1] += arr[i][2];
		}
		else {
			arr[i + 1][1] += arr[i][0];
		}
		if (arr[i][0] > arr[i][1]) {
			arr[i + 1][2] += arr[i][1];
		}
		else {
			arr[i + 1][2] += arr[i][0];
		}
	}

	int max = 2147483647;
	for (int j = 0; j < 3; j++) {
		if (max > arr[input - 1][j]) {
			max = arr[input - 1][j];
		}
	}
	cout << max << endl;
	
	for (int j = 0; j < 3; j++) {
		delete[] * (arr + j);
	}
	delete[] arr;
	return 0;
}