#include <iostream>
using namespace std;

#define N 100



class my_matrix {
    int matrix[N][N]; 
    int max_entries;
  public:
    void set_values (int _max_entries);
    void set_entries () ;
    int trace () ;
    int determinant();

};

void my_matrix::set_values (int _max_entries) {
  max_entries = _max_entries ;
}


void my_matrix::set_entries () 
 {
 //declaring the entries of the 2 dimensional array.
 for (int i = 0 ; i < max_entries ; ++i )
	for (int j = 0 ; j <  max_entries ;++j)
		matrix[i][j] = i+j + 1 ;
 }

int my_matrix::trace() 
 {
 int return_value = 0 ;
 for (int i = 0 ; i < max_entries ; ++ i)
	return_value +=matrix[i][i] ;
 
 return return_value ;
 }

int main () {
  int n ;
  my_matrix mat ;
  cout << " This program calculates the trace of a matrix. " << endl;
  cout << " Please enter the dimension of the matrix: " ;
  cin >> n;
  mat.set_values (n);
  mat.set_entries();
  
  cout << "trace of the matrix " << mat.trace() << endl;
 
return 0; 
}