#include<cstdio>
#include<algorithm>
#include<cstring>

#define A strlen(a)
#define B strlen(b)
#define ANS strlen(ans)

using namespace std;
int main(){
    int n;
    scanf("%d",&n);
    char x=0;
    for(int q = 0;q < n; q++){
        int f = 0;
        bool check[1000]={0};
        char a[1000]={0},b[1000]={0},ans[1000]={0};
        scanf("%s%s",a,b);
        reverse(a,a+A);
        reverse(b,b+B);

        int len1 = max(A,B);
        int len2 = min(A,B);

        (len1 == A) ? f=1 : f=2;

        if(len2 > 80 || len1 > 80){
            printf("overflow\n");
            continue;
        }

        for(int i = 0;i < len1; i++){
            if(a[i] == '0' && b[i] != '0'){
                b[i] -= 48;
                ans[i] = b[i];
                continue;
            }
            if(a[i] != '0' && b[i] == '0'){
                a[i] -= 48;
                ans[i] = a[i];
                continue;
            }
            if(a[i] == '0' && b[i] == '0'){
                ans[i] = '0';
                check[i] = 1;
                continue;
            }
            //printf("uu%d %d\n",A,B);
            if(i >= len2){
                //printf("('ω')v\n");
                //printf("f = %d\n",f);
                if(f == 1)ans[i] = a[i];
                if(f == 2)ans[i] = b[i];
                check[i] = 1;
                continue;
            }
            a[i] -= 48;
            b[i] -= 48;
            x = a[i] + b[i];
            ans[i]= x;
        }
        for(int i = 0;i < ANS; i++){
            if(check[i] == 1){
                if(ans[i] >= 58){
                    if(ans[i] == 58){
                        ans[i] = '0';
                        ans[i+1]++;
                        continue;
                    }
                    else {
                        ans[i] -= 10;
                        ans[i+1]++;
                    }
                }
                continue;
            }
            else if(ans[i] >= 10){
                //printf("yo-yo-\n");
                if(ans[i] == 10){
                    ans[i] = '0';
                    ans[i+1]++;
                    continue;
                }
                else {
                    ans[i] = ans[i] - 10;
                    ans[i+1]++;
                }
            }
            ans[i] += 48;
        }

        reverse(ans,ans+ANS);

        (ANS > 80) ? printf("overflow\n") : printf("%s\n",ans);
    }
    return 0;
}