#include <bits/stdc++.h>
using namespace std;
auto start = std::chrono::system_clock::now();
inline void skj() {
  std::chrono::time_point<std::chrono::system_clock> end;
  end = std::chrono::system_clock::now();
  std::chrono::duration<double> elapsed_seconds = end - start;
  std::time_t end_time = std::chrono::system_clock::to_time_t(end);
  cerr << "Time taken " << elapsed_seconds.count() * 1000 << "\n";
}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
struct custom_hash {
  static uint64_t splitmix64(uint64_t x) {
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }
  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};
inline long long binexp(long long a, long long b, long long m) {
  if (a == 0) {
    return 0;
  }
  long long res = 1;
  a %= m;
  while (b) {
    if (b & 1) res = (res * 1ll * a) % m;
    a = (a * 1ll * a) % m;
    b >>= 1;
  }
  return res;
}
inline long long binmul(long long a, long long b, long long m) {
  a %= m;
  long long res = 0;
  while (b) {
    if (b & 1) {
      res = (res + a) % m;
    }
    a = (a + a) % m;
    b >>= 1;
  }
  return res;
}
inline void solve_me_senpai() {
  long long n, m, l, r;
  cin >> n >> m >> l >> r;
  long long t1 = (r - l + 1) / 2, t2 = r - l + 1 - t1;
  long long ans;
  if ((n * m) & 1) {
    ans = (binexp(t1 + t2, n * m, 998244353) +
           binexp((t1 - t2 + 998244353) % 998244353, n * m, 998244353) +
           998244353) %
          998244353;
    ans = (ans * binexp(2, 998244353 - 2, 998244353)) % 998244353;
    long long tans =
        (binexp(t1 + t2, n * m, 998244353) +
         binexp((t2 - t1 + 998244353) % 998244353, n * m, 998244353)) %
        998244353;
    tans = (tans * binexp(2, 998244353 - 2, 998244353)) % 998244353;
    ans = (ans + tans) % 998244353;
  } else {
    ans = (binexp(t1 + t2, n * m, 998244353) +
           binexp((t1 - t2 + 998244353) % 998244353, n * m, 998244353)) %
          998244353;
    ans = (ans * binexp(2, 998244353 - 2, 998244353)) % 998244353;
  }
  cout << ans;
}
int32_t main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long t = 1;
  long long a = 1;
  while (t--) {
    solve_me_senpai();
    a++;
  }
  return 0;
}
