給不會用python的人
int main(){
vector <int> v;
string s, t;
stringstream s1;
getline(cin, s);
while(cin>>t){
continue;
}
s1.str("");
s1.clear();
s1<<s;
while(true){
int i;
s1>>i;
if(s1.fail())break;
v.push_back(i);
}
int n;
n = v.size()/2;
cout << v[n] <<endl;
}