#include<bits/stdc++.h>
using namespace std;
int main(){
// #ifndef ONLINE_JUDGE
// freopen("input.txt","r",stdin);
// freopen("output.txt", "w", stdout);
// #endif
vector<pair<int,int>>v;
int n; cin>>n;
int a,b;
// cout<<n<<endl;
for(int i=0;i<n;i++){
cin>>a;
cin>>b;
v.push_back( make_pair(a,b) );
// v[i].first=a;
// v[i].second=b;
// v[i]={a,b};
}
for(int i=0;i<n;i++){
cout<<v[i].first<<" ";
cout<<v[i].second<<" ";
}
return 0;
}
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