#include <iostream>
using namespace std;
int main()
{
int a,b;
while(1)
{
cin>>a>>b;
if(a==0&&b==0)
break;
cout<<a+b<<endl;
}
return 0;
}
HDU_A+B for Input-Output Practice (III)

#include <iostream>
using namespace std;
int main()
{
int a,b;
while(1)
{
cin>>a>>b;
if(a==0&&b==0)
break;
cout<<a+b<<endl;
}
return 0;
}