[1149번] RGB거리

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;
import java.util.StringTokenizer;
 
public class Main {
    static int z=0;
    static int o=0;
    static int[] a = { 0, 0 };
 
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
 
        int T = sc.nextInt();
        int[][] ar = new int[T][3];
        int[][] dp = new int[T][3];
        for(int i=0;i<T;i++){
            for(int j=0;j<3;j++){
                ar[i][j] = sc.nextInt();
            }
        }
        dp[0][0] = ar[0][0];
        dp[0][1] = ar[0][1];
        dp[0][2] = ar[0][2];
        
        for(int i=1;i<T;i++){
            for(int j=0;j<3;j++){
                if(j==0){
                    dp[i][j] = Math.min(ar[i][j]+dp[i-1][j+1], ar[i][j]+dp[i-1][j+2]);
                }else if(j==1){
                    dp[i][j] = Math.min(ar[i][j]+dp[i-1][j-1], ar[i][j]+dp[i-1][j+1]);
                }else{
                    dp[i][j] = Math.min(ar[i][j]+dp[i-1][j-1], ar[i][j]+dp[i-1][j-2]);
                }
            }
        }
        System.out.println(Math.min(dp[T-1][0],Math.min(dp[T-1][1], dp[T-1][2])));
 
        
 
 
    } 
}
 
class FastScanner {
    BufferedReader br;
    StringTokenizer st;
 
    public FastScanner(String s) {
        try {
            br = new BufferedReader(new FileReader(s));
        } catch (FileNotFoundException e) {
            throw new RuntimeException(e);
        }
    }
 
    public FastScanner() {
        br = new BufferedReader(new InputStreamReader(System.in));
    }
 
    String nextToken() {
        while (st == null || !st.hasMoreElements()) {
            try {
                st = new StringTokenizer(br.readLine());
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
        }
        return st.nextToken();
    }
 
    int nextInt() {
        return Integer.parseInt(nextToken());
    }
 
    long nextLong() {
        return Long.parseLong(nextToken());
    }
 
    double nextDouble() {
        return Double.parseDouble(nextToken());
    }
 
    String nextLine() {
        String str = "";
        try {
            str = br.readLine();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return str;
    }
}