souvenirs.cpp: In function 'void buy_souvenirs(int, long long int)':
souvenirs.cpp:2:14: error: 'vector' was not declared in this scope
2 | pair<vector<int>, long long> res = transaction(P0-1);
| ^~~~~~
souvenirs.cpp:2:9: error: 'pair' was not declared in this scope
2 | pair<vector<int>, long long> res = transaction(P0-1);
| ^~~~
souvenirs.cpp:2:21: error: expected primary-expression before 'int'
2 | pair<vector<int>, long long> res = transaction(P0-1);
| ^~~
souvenirs.cpp:3:15: error: 'res' was not declared in this scope
3 | int a=res.second;
| ^~~
souvenirs.cpp:7:13: error: 'transaction' was not declared in this scope
7 | transaction(P0/2);
| ^~~~~~~~~~~
souvenirs.cpp:13:17: error: 'transaction' was not declared in this scope
13 | transaction(P0-1);
| ^~~~~~~~~~~