#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <vector>
#include <algorithm>
#include <cmath>
#include <math.h>
#include <set>
#include <map>
#include <queue>
#include <deque>
#include <stack>

#define pb push_back
#define ff first
#define ss second
#define sqr(x) (x) * (x)
#define cb(x) (x) * (x) * (x)
#define SIZE 101
#define INF 1e18 + 9

using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

const int inf = 2e9;
ll linf = 2e18;

template <typename T>
ostream& operator << (ostream& s, vector<T>& v) {
	for (auto el : v) {
		s << el << " ";
	}
	return s;
}



int main() {
//3
	ios_base::sync_with_stdio(0);
	cin.tie(0), cout.tie(0);

	int n; cin >> n; n++;
	vector<int> a(n), b(n), c(n);
	for (int i = 1; i < n; i++)
		cin >> a[i] >> b[i] >> c[i];

	vector<ll> dp(n);
	dp[1] = a[1];

	for (int i = 2; i < n; i++) {
		dp[i] = dp[i - 1] + a[i];
		dp[i] = min(dp[i], dp[i - 2] + b[i - 1]);
		if (i > 2) dp[i] = min(dp[i], dp[i - 3] + c[i - 2]);
	}

	cout << dp[n - 1] << endl;
	return 0;
}