#include <bits/stdc++.h>

#define rep(i, n) for (int i = 0; i < int(n); i++)
#define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--)
#define reps(i, n) for (int i = 1; i <= int(n); i++)
#define rreps(i, n) for (int i = int(n); i >= 1; i--)
#define repc(i, n) for (int i = 0; i <= int(n); i++)
#define rrepc(i, n) for (int i = int(n); i >= 0; i--)
#define repi(i, a, b) for (int i = int(a); i < int(b); i++)
#define repic(i, a, b) for (int i = int(a); i <= int(b); i++)
#define each(x, y) for (auto &x : y)
#define all(a) (a).begin(), (a).end()
#define bit(b) (1ll << (b))

using namespace std;

using i32 = int;
using i64 = long long;
using u64 = unsigned long long;
using f80 = long double;
using vi32 = vector<i32>;
using vi64 = vector<i64>;
using vu64 = vector<u64>;
using vf80 = vector<f80>;
using vstr = vector<string>;

inline void yes() { cout << "Yes" << '\n'; exit(0); }
inline void no() { cout << "No" << '\n'; exit(0); }
inline i64 gcd(i64 a, i64 b) { if (min(a, b) == 0) return max(a, b); if (a % b == 0) return b; return gcd(b, a % b); }
inline i64 lcm(i64 a, i64 b) { return a / gcd(a, b) * b; }
inline u64 xorshift() { static u64 x = 88172645463325252ull; x = x ^ (x << 7); return x = x ^ (x >> 9); }
void solve(); int main() { ios::sync_with_stdio(0); cin.tie(0); cout << fixed << setprecision(16); solve(); return 0; }
template <typename T> class pqasc : public priority_queue<T, vector<T>, greater<T>> {};
template <typename T> class pqdesc : public priority_queue<T, vector<T>, less<T>> {};
template <typename T> inline void amax(T &x, T y) { if (x < y) x = y; }
template <typename T> inline void amin(T &x, T y) { if (x > y) x = y; }
template <typename T> inline T power(T x, i64 n, T e = 1) { T r = e; while (n > 0) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; }
template <typename T> istream& operator>>(istream &is, vector<T> &v) { each(x, v) is >> x; return is; }
template <typename T> ostream& operator<<(ostream &os, vector<T> &v) { rep(i, v.size()) { if (i) os << ' '; os << v[i]; } return os; }
template <typename T, typename S> istream& operator>>(istream &is, pair<T, S> &p) { is >> p.first >> p.second; return is; }
template <typename T, typename S> ostream& operator<<(ostream &os, pair<T, S> &p) { os << p.first << ' ' << p.second; return os; }

void solve() {
  int N; cin >> N;
  rep(i, N) {
    string s, t;
    cin >> s >> t;
    if (s.size() > 80 || t.size() > 80) {
      cout << "overflow" << '\n';
      continue;
    }
    if (s == "0") {
      cout << t << '\n';
      continue;
    } else if (t == "0") {
      cout << s << '\n';
      continue;
    }
    string ans = "";
    bool up = false;
    rep(i, min(s.size(), t.size())) {
      int a = s[s.size() - 1 - i] - '0';
      int b = t[t.size() - 1 - i] - '0';
      int x = up ? 1 : 0;
      up = false;
      x += a + b;
      if (x >= 10) up = true, x -= 10;
      string te;
      te += (char) x + '0';
      ans = te + ans;
    }
    repi(i, min(s.size(), t.size()), max(s.size(), t.size())) {
      int a;
      if (i >= s.size()) a = t[t.size() - i - 1] - '0';
      else a = s[s.size() - i - 1] - '0';
      int x = up ? 1 : 0;
      up = false;
      x += a;
      if (x >= 10) up = true, x -= 10;
      string te;
      te += (char) x + '0';
      ans = te + ans;
    }
    if (up) {
      ans = "1" + ans;
    }
    if (ans.size() > 80) {
      cout << "overflow" << '\n';
      continue;
    }
    cout << ans << '\n';
  }
}



Measured memory_bytes: 3032