#include <iostream>
using namespace std;
int main ()
{
int a,b;
while(cin>>a>>b)
{
cout<<(a+b)/2<<endl;
}
return 0;
}
#include <iostream>
using namespace std;
int main ()
{
int a,b;
while(cin>>a>>b)
{
cout<<(a+b)/2<<endl;
}
return 0;
}