#include <algorithm>
#include <iostream>

using namespace std;


int main(){
    int n;
    int arr[5001][3], res[5002];

    scanf("%d", &n);

    for (int i = 0; i < n; i++){
        scanf("%d %d %d", &arr[i][0], &arr[i][1], &arr[i][2]);
    }

    for (int i = 0; i < n; i++){
        for (int j = 1; j <= 3 && i + j <= n; j++){
            if (!res[i + j] || res[i + j] > res[i] + arr[i][j - 1]){
                res[i + j] = res[i] + arr[i][j - 1];
            }
        }
    }
    printf("%d", res[n]);
}