#include<iostream>
#include<string>
typedef unsigned int u;using namespace std;typedef string::iterator s;u z=100000000;void p(u*a,u*l,u n){if(a-l)p(a+1,l,(n+=*a*10)/z),*a=n%z;}u t(u*a,u*l){u r=0;char b[11]={};if(a-l)if(!t(a+1,l)){if(*a)cout<<*a,r=1;}else sprintf(b,"%d",*a+z),cout<<b+1,r=1;return r;}void d(u*a,u*l,u*b,u n=0){if(a-l)d(a+1,l,b+1,(n+=(*a+*b))/z),*a=n%z;}int main(){u n;(cin>>n).ignore();string a,b;for(;n--;){getline(cin,a);getline(cin,b);u x[11]={},y[11]={},c=0;for(s i=a.begin();i!=a.end();p(x,x+10,*i++-48))if(++c>80)goto g;c=0;for(s i=b.begin();i!=b.end();p(y,y+10,*i++-48))if(++c>80)goto g;d(x,x+11,y);if(x[10])goto g;else if(!t(x,x+10))cout<<'0';if(0)g:cout<<"overflow";cout<<'\n';}}