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