#include <iostream>
using namespace std;
int main()
{
int i =0;
for (i=0;i<20;i++)
{
switch(i)
{
case 0:
i+=5;
cout<< i<<" ";
case 1:
i+=2;
cout<< i<<" ";
case 5:
i+=5;
cout<< i<<" ";
default:
i+=4;
cout<< i<<" ";
break;
}
cout<< i<<" ";
}
return 0;
}
//ans: 5 7 12 16 16 21 21