#if __INCLUDE_LEVEL__ == 0

#include __BASE_FILE__

using Fp = atcoder::modint998244353;

using M = array<array<Fp, 2>, 2>;

namespace atcoder {

M operator*(const M& x, const M& y) {
  return {
      x[0][0] * y[0][0] + x[0][1] * y[1][0],
      x[0][0] * y[0][1] + x[0][1] * y[1][1],
      x[1][0] * y[0][0] + x[1][1] * y[1][0],
      x[1][0] * y[0][1] + x[1][1] * y[1][1],
  };
}

M& operator*=(M& x, const M& y) { return x = x * y; }

array<Fp, 2> operator*(const M& f, const array<Fp, 2>& x) {
  return {
      f[0][0] * x[0] + f[0][1] * x[1],
      f[1][0] * x[0] + f[1][1] * x[1],
  };
}

}  // namespace atcoder

namespace {

void solve() {
  static vector<M> pref;
  static vector<M> suff;
  if (pref.empty()) {
    constexpr int N = 1e7;
    pref.resize(N + 1);
    pref[0] = {1, 0, 0, 1};
    for (int n : rep1(N)) {
      pref[n] = M{0, 1, n - 1, n * 2} * pref[n - 1];
    }
    suff.resize(N + 1);
    suff[0] = {1, 0, 0, 1};
    for (int n : rep1(N)) {
      suff[n] = suff[n - 1] * M{0, 1, n, n * 2};
    }
  }
  int64_t n, m;
  scan(n, m);
  if (m < n) {
    swap(n, m);
  }
  array<Fp, 2> f{0, 1};
  f = pref[n] * f;
  if (n < m) {
    f = power<M>({0, 1, n, n * 2 + 1}, m - n) * f;
  }
  f = suff[n] * f;
  print(f[1]);
}

}  // namespace

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  int t;
  scan(t);
  while (t--) {
    solve();
  }
}

#else  // __INCLUDE_LEVEL__

#include <bits/stdc++.h>

using namespace std;

#include <atcoder/modint>

template <class T, class N>
constexpr T power(T x, N n) {
  assert(0 < n);
  while (n % 2 == 0) {
    x *= x;
    n >>= 1;
  }
  T ret = x;
  while (n >>= 1) {
    x *= x;
    if (n % 2) {
      ret *= x;
    }
  }
  return ret;
}

namespace std {

template <class T1, class T2>
istream& operator>>(istream& is, pair<T1, T2>& p) {
  return is >> p.first >> p.second;
}

template <class... Ts>
istream& operator>>(istream& is, tuple<Ts...>& t) {
  return apply([&is](auto&... xs) -> istream& { return (is >> ... >> xs); }, t);
}

template <class R, enable_if_t<!is_convertible_v<R, string>>* = nullptr>
auto operator>>(istream& is, R&& r) -> decltype(is >> *begin(r)) {
  for (auto&& e : r) {
    is >> e;
  }
  return is;
}

template <class T1, class T2>
ostream& operator<<(ostream& os, const pair<T1, T2>& p) {
  return os << p.first << ' ' << p.second;
}

template <class... Ts>
ostream& operator<<(ostream& os, const tuple<Ts...>& t) {
  auto f = [&os](const auto&... xs) -> ostream& {
    [[maybe_unused]] auto sep = "";
    ((os << exchange(sep, " ") << xs), ...);
    return os;
  };
  return apply(f, t);
}

template <class R, enable_if_t<!is_convertible_v<R, string_view>>* = nullptr>
auto operator<<(ostream& os, R&& r) -> decltype(os << *begin(r)) {
  auto sep = "";
  for (auto&& e : r) {
    os << exchange(sep, " ") << e;
  }
  return os;
}

}  // namespace std

namespace atcoder {

template <class T, internal::is_modint_t<T>* = nullptr>
istream& operator>>(istream& is, T& x) {
  int v;
  is >> v;
  x = T::raw(v);
  return is;
}

template <class T, internal::is_modint_t<T>* = nullptr>
ostream& operator<<(ostream& os, const T& x) {
  return os << x.val();
}

}  // namespace atcoder

template <class... Ts>
void scan(Ts&&... xs) {
  (cin >> ... >> xs);
}

template <class... Ts>
void print(Ts&&... xs) {
  cout << tie(xs...) << '\n';
}

inline auto rep(int l, int r) { return views::iota(min(l, r), r); }
inline auto rep(int n) { return rep(0, n); }
inline auto rep1(int l, int r) { return rep(l, r + 1); }
inline auto rep1(int n) { return rep(1, n + 1); }
inline auto per(int l, int r) { return rep(l, r) | views::reverse; }
inline auto per(int n) { return per(0, n); }
inline auto per1(int l, int r) { return per(l, r + 1); }
inline auto per1(int n) { return per(1, n + 1); }

inline auto len = ranges::ssize;

#endif  // __INCLUDE_LEVEL__