int main() {
ofstream fout("data.txt");
fout << 10 << " " << 20 << endl;
fout << 30 << " " << 40;
fout.close();

ifstream fin("data.txt");
int a, b, c, d;
fin >> a >> b >> c >> d;
fin.close();

cout << a + b + c + d;
return 0;
}