Language: C++

#include<bits/stdc++.h>
using namespace std;

int main(){
  
  vector<vecto<int>> vec(3, vector<int>(3));
  for (int i=0; i<3; i++){
    for (int j=0; j<3; j++){
      cin >> vec.at(i).at(j);
    }
  }
  
  vector<int> det(6);
  det.at(0) = vec.at(0).at(0)+vec.at(1).at(1)+vec.at(2).at(2);
  det.at(1) = vec.at(0).at(1)+vec.at(1).at(0)+vec.at(2).at(2);
  det.at(2) = vec.at(0).at(2)+vec.at(2).at(0)+vec.at(1).at(1);
  det.at(3) = vec.at(1).at(0)+vec.at(2).at(0)+vec.at(1).at(2);
  det.at(4) = vec.at(0).at(0)+vec.at(1).at(2)+vec.at(2).at(1);
  det.at(5) = vec.at(0).at(1)+vec.at(0).at(2)+vec.at(2).at(1);
  
  bool f = true;
  for (int i=1; i<6; i++){
    if (det.at(0) != det.at(i)){
      f = false;
      break;
    }
  }
  
  if (f) cout << "Yes" << endl;
  else cout << "No" << endl;
  
}

Compiler output:
a.cc: In function 'int main()':
a.cc:6:10: error: 'vecto' was not declared in this scope
    6 |   vector<vecto<int>> vec(3, vector<int>(3));
      |          ^~~~~
a.cc:6:19: error: template argument 1 is invalid
    6 |   vector<vecto<int>> vec(3, vector<int>(3));
      |                   ^~
a.cc:6:19: error: template argument 2 is invalid
a.cc:6:43: error: expression list treated as compound expression in initializer [-fpermissive]
    6 |   vector<vecto<int>> vec(3, vector<int>(3));
      |                                           ^
a.cc:6:29: error: cannot convert 'std::vector<int>' to 'int' in initialization
    6 |   vector<vecto<int>> vec(3, vector<int>(3));
      |                             ^~~~~~~~~~~~~~
      |                             |
      |                             std::vector<int>
a.cc:9:18: error: request for member 'at' in 'vec', which is of non-class type 'int'
    9 |       cin >> vec.at(i).at(j);
      |                  ^~
a.cc:14:19: error: request for member 'at' in 'vec', which is of non-class type 'int'
   14 |   det.at(0) = vec.at(0).at(0)+vec.at(1).at(1)+vec.at(2).at(2);
      |                   ^~
a.cc:14:35: error: request for member 'at' in 'vec', which is of non-class type 'int'
   14 |   det.at(0) = vec.at(0).at(0)+vec.at(1).at(1)+vec.at(2).at(2);
      |                                   ^~
a.cc:14:51: error: request for member 'at' in 'vec', which is of non-class type 'int'
   14 |   det.at(0) = vec.at(0).at(0)+vec.at(1).at(1)+vec.at(2).at(2);
      |                                                   ^~
a.cc:15:19: error: request for member 'at' in 'vec', which is of non-class type 'int'
   15 |   det.at(1) = vec.at(0).at(1)+vec.at(1).at(0)+vec.at(2).at(2);
      |                   ^~
a.cc:15:35: error: request for member 'at' in 'vec', which is of non-class type 'int'
   15 |   det.at(1) = vec.at(0).at(1)+vec.at(1).at(0)+vec.at(2).at(2);
      |                                   ^~
a.cc:15:51: error: request for member 'at' in 'vec', which is of non-class type 'int'
   15 |   det.at(1) = vec.at(0).at(1)+vec.at(1).at(0)+vec.at(2).at(2);
      |                                                   ^~
a.cc:16:19: error: request for member 'at' in 'vec', which is of non-class type 'int'
   16 |   det.at(2) = vec.at(0).at(2)+vec.at(2).at(0)+vec.at(1).at(1);
      |                   ^~
a.cc:16:35: error: request for member 'at' in 'vec', which is of non-class type 'int'
   16 |   det.at(2) = vec.at(0).at(2)+vec.at(2).at(0)+vec.at(1).at(1);
      |                                   ^~
a.cc:16:51: error: request for member 'at' in 'vec', which is of non-class type 'int'
   16 |   det.at(2) = vec.at(0).at(2)+vec.at(2).at(0)+vec.at(1).at(1);
      |                                                   ^~
a.cc:17:19: error: request for member 'at' in 'vec', which is of non-class type 'int'
   17 |   det.at(3) = vec.at(1).at(0)+vec.at(2).at(0)+vec.at(1).at(2);
      |                   ^~
a.cc:17:35: error: request for member 'at' in 'vec', which is of non-class type 'int'
   17 |   det.at(3) = vec.at(1).at(0)+vec.at(2).at(0)+vec.at(1).at(2);
      |                                   ^~
a.cc:17:51: error: request for member 'at' in 'vec', which is of non-class type 'int'
   17 |   det.at(3) = vec.at(1).at(0)+vec.at(2).at(0)+vec.at(1).at(2);
      |                                                   ^~
a.cc:18:19: error: request for member 'at' in 'vec', which is of non-class type 'int'
   18 |   det.at(4) = vec.at(0).at(0)+vec.at(1).at(2)+vec.at(2).at(1);
      |                   ^~
a.cc:18:35: error: request for member 'at' in 'vec', which is of non-class type 'int'
   18 |   det.at(4) = vec.at(0).at(0)+vec.at(1).at(2)+vec.at(2).at(1);
      |                                   ^~
a.cc:18:51: error: request for member 'at' in 'vec', which is of non-class type 'int'
   18 |   det.at(4) = vec.at(0).at(0)+vec.at(1).at(2)+vec.at(2).at(1);
      |                                                   ^~
a.cc:19:19: error: request for member 'at' in 'vec', which is of non-class type 'int'
   19 |   det.at(5) = vec.at(0).at(1)+vec.at(0).at(2)+vec.at(2).at(1);
      |                   ^~
a.cc:19:35: error: request for member 'at' in 'vec', which is of non-class type 'int'
   19 |   det.at(5) = vec.at(0).at(1)+vec.at(0).at(2)+vec.at(2).at(1);
      |                                   ^~
a.cc:19:51: error: request for member 'at' in 'vec', which is of non-class type 'int'
   19 |   det.at(5) = vec.at(0).at(1)+vec.at(0).at(2)+vec.at(2).at(1);
      |                                                   ^~