#include<iostream>
#include<string>
#include<stack>
using namespace std;

int main(){
    
    int n;
    string str1,str2;
    stack<int> st;
    
    cin >> n;
    while(n--){
        cin >> str1 >> str2;
        int i,j,num1,num2,kuri,sum;
        i = str1.size()-1;
        j = str2.size()-1;
        kuri = 0;
        while(i>=0 || j>=0){
            num1 = 0;
            num2 = 0;
            if(i >= 0) num1 = str1[i]-'0';
            if(j >= 0) num2 = str2[j]-'0';
            sum = num1+num2+kuri;
            st.push(sum%10);
            kuri = 0;
            if(sum >= 10) kuri = 1;
            i--;
            j--;
        }
        if(st.size()+kuri > 80){
            cout << "overflow" << endl;
            while(!st.empty()) st.pop();
            continue;
        }
        if(kuri == 1) cout << 1;
        while(!st.empty()){
            cout << st.top();
            st.pop();
        }
        cout << endl;
    }
    
    return(0);
}
