#include<bits/stdc++.h> using namespace std; int main(){ int n,a[101],x; cin>>n; for(int i = 1;i<=n;i++){ cin>>a[i]; } for(int i = 2;i<=n;i+=2){ x=a[i-1]; a[i-1]=a[i]; a[i]=x; } for(int i = 1;i<=n;i++){ cout<<a[i]<<" "; } }