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#include<iostream> #include<cstdio> #include<algorithm> #include<vector> using namespace std; //using std::vector; vector<int>a(1); int main() { int n,x,m; cin>>n; for(int i=1;i<=n;i++) { cin>>x; a.push_back(x); } cout<<a.size(); cin>>m; cout<<a.at(m)<<endl; cout<<"first"<<a.front()<<endl; cout<<"last"<<a.back(); }