#include <iostream>
#include <vector>
using namespace std;
int main() {
vector <double> s;
double a,n;
int b=0;
while(cin>>a)
{
s.push_back(a);
}
n=s.size()/2;
for(int i=0;i<n;i++)
{
s.insert(s.begin()+2*i+1,s.at(n+b+i));
b++;
}
s.resize(2*n);
for(int i=0;i<s.size();i++)
{
cout<<s.at(i)<<" ";
}
return 0;
}
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