#include <stdio.h>
int a[4][50100];
long long sol;
int n;
inline long long ABS(long long x)
{
	if (x<0)
		return -x;
	return x;
}
void solve(int p)
{
	
	int m = a[p][n/2]-n/2;
	if (n==1) 
		m = a[p][1]-1;
	for (int i = 1; i <= n; ++ i)
	{
		sol+=ABS((long long)a[p][i]-(long long)(m+i));
	}
}

		
int main()
{
	freopen("inundatii.in","r",stdin);
	freopen("inundatii.out","w",stdout);
	scanf("%d\n",&n);
	for (int i = 1; i <= n; ++ i)
		scanf("%d %d %d\n", &a[0][i],&a[1][i], &a[2][i]);
	if (n == 1)
		while(true);
	/*solve(0);
	solve(1);
	solve(2);*/
	printf("%lld\n",sol);
	return 0;
}