#include <fstream>
std::ifstream f1("inundatii.in");
std::ofstream f2("inundatii.out");
int main()
{
	long n, i, x[50000], y[50000], z[50000];
	unsigned long long sol=0;
	f1>>n;
	for (i=0; i<n; i++)
	{
		f1>>x[i]>>y[i]>>z[i];
	}//for i
	for (i=(n-2); i>=0; i--)
	{
		if (x[i]>x[i+1])
		{
			sol+=x[i]-x[i+1]+1;
			x[i]=x[i+1]-1;
		}//if
		if (y[i]>y[i+1])
		{
			sol+=y[i]-y[i+1]+1;
			y[i]=y[i+1]-1;
		}//if
		if (z[i]>z[i+1])
		{
			sol+=z[i]-z[i+1]+1;
			z[i]=z[i+1]-1;
		}//if
	}//for i
	f2<<sol;
	f1.close();
	f2.close();
	return 0;
}//main