#include <cstdio>
#include <cstring>

int main(){
 int n;
 scanf("%d\n",&n);
 for(int x = 0;x < n;x++){
  char A[101],B[101];
  scanf("%s\n%s\n",A,B);
  
  int l_a,l_b;
  if((l_a = strlen(A)) > 80 || (l_b = strlen(B)) > 80){
   printf("overflow\n");
  }
  int val[81];
  int i;
  for(i = 0;i < l_a || i <l_b;i++){
   if(l_a - i > 0) val[i] += A[l_a - i - 1] - '0';
   if(l_b - i > 0) val[i] += B[l_b - i - 1] - '0';
  }
  bool flg = false;
  for(int j = i;j >= 0;j--){
   if(val[j] >= 10){
    if(j - 1 < 0) flg = true;
    else          val[j] -= 10,val[j - 1]++;
   }
  }
  if(flg){
   printf("overflow\n");
  }else{
   for(;i >= 0;i--){
    printf("%d",val[i]);
   }
   printf("\n");
  }
 }
 return 0;
}