# include<stdio.h> # include<iostream> using namespace std; int main(){ int n; cin>>n; int a[n]; for(int i=0;i<n;i++){ cin>>a[i]; } int t; for(int i=0;i<=n-2;i=i+2){ t=a[i]; a[i]=a[i+1]; a[i+1]=t; } for(int i=0;i<n;i++){ cout<<a[i]<<" "; } return 0; }