#include <fstream>

using namespace std;

ifstream cin ("inundatii.in");
ofstream cout ("inundatii.out");

#define NMAX 50005

int cladiri[NMAX][3];
int answer[NMAX][3];

int main() {
    int n, j, i, cost;
    cin >> n;
    for ( i = 1; i <= n; i++ ) {
        cin >> cladiri[i][0] >> cladiri[i][1] >> cladiri[i][2];
    }
    cost = 0;
    for ( j = 0; j < 3; j++ ) {
        answer[1][j] = cladiri[1][j];
        for ( i = 2; i <= n; i++ ) {
          if ( cladiri[i][j] <= answer[i - 1][j] ) {
            cost += abs( answer[i - 1][j] + 1 - cladiri[i][j] );
            answer[i][j] = answer[i - 1][j] + 1;
          }
          else
            answer[i][j] = cladiri[i][j];
        }
    }
    cout << cost;
    return 0;
}