text: #include <iostream>
  #include <fstream>
  #include <string>
  
  using namespace std;
  
  int main()
  {
  	const int capacity = 300;
  	int s[capacity], i, nr = 0, n, sum = 0, numar;
  
  	ifstream file;
  	file.open("SIR.TXT");
  
  	if (file.fail())
  	{
  		cerr << "FILE ERROR" << endl;
  		exit(1);
  	}
  
  	while (!file.eof())
  		{
  			file >> n;
  			sum += n;
  			nr++;
  		}
  	file.close();
  
  	numar = ((nr + 1)*(nr + 2)) / 2 - sum;
  	cout << "nr lipsa e: " << numar << endl;
  
  	return 0;
  }