#include <bits/stdc++.h> using namespace std; int main() { int a,c; cin>>a; int b[a]; for(int i = 0;i <= a-1;i++) cin>>b[i]; for(int i = 0;i <= a/2;i+=2) { c = b[i]; b[i] = b[i+1]; b[i+1] = c; } for(int i = 0;i <= a-1;i++) cout<<b[i]<<' '; return 0; }