#include <iostream> #include <vector> #include <string> #include <sstream> using namespace std; int main() { int n; cin >> n; vector<int> a(n); for (int i = 0; i < n; ++i) { cin >> a[i]; } for (int i = 0; i < n - 1; i += 2) { swap(a[i], a[i + 1]); } for (int i = 0; i < n; ++i) { if (i > 0) { cout << " "; } cout << a[i]; } cout << endl; return 0; }