#include <stdio.h>
 
int N, price[1001][3];
int dp[1001];
 
void read();
int min(int a, int b);
 
int main(void)
{
	int i = 0;
 
	read();
 
	dp[1] = min(min(price[1][0], price[1][1]), price[1][2]);
 
	for(i = 2; i <= N; ++i)
		dp[i] = dp[i - 1] + min(min(price[i][0], price[i][1]), price[i][2]);
 
	printf("%d\n", dp[N]);
 
	return 0;
}
 
void read()
{
	int i = 0;
 
	scanf("%d", &N);
	for(i = 1; i <= N; ++i)
	{
		scanf("%d", &price[i][0]);
		scanf("%d", &price[i][1]);
		scanf("%d", &price[i][2]);
	}
}
 
int min(int a, int b)
{
	return (a > b) ? b : a;
}

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

MwoyNiA0MCA4Mwo0OSA2MCA1NwoxMyA4OSA5OQ==

3
26 40 83
49 60 57
13 89 99