Покупка билетов

#include <bits/stdc++.h>

using namespace std;

const int N = 5005;

int n;
long long a[N], b[N], c[N], dp[N];

int main(){
    cin >> n;

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

    dp[1] = a[1];
    dp[2] = min(a[1] + a[2], b[1]);

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

    cout << dp[n] << endl;
}