#include<iostream> using namespace std; int main(){ int a[100000]={},n,m; cin>>n; for(int i=0;i<n;i++){ cin>>a[i]; } for(int i=0;i<n;i+2){ if(i%2==0){ m=a[i-1]; a[i-1]=a[i]; a[i-1]=m;} cout<<a[i];} return 0; }