include

include

include

using namespace std;

int main() {

list<int>a;
int x, sum = 0;
cin >> x;
int s;
cin >> s;
for (; x != -1;) {
	if (a.size() > 0) {
		a.pop_back();
	}else {
		cout << "not found";
	}
	
	if (sum = s) {
		cout << ;
	} 
}

return 0;

}