#include <bits/stdc++.h>
#pragma GCC optimize("-O3")
using namespace std;
const long long N = 1e6 + 5;
long long mod = 998244353;
void pairsort(long long a[], long long b[], long long n) {
  pair<long long, long long> pairt[n];
  for (long long i = 0; i < n; i++) {
    pairt[i].first = a[i];
    pairt[i].second = b[i];
  }
  sort(pairt, pairt + n);
  for (long long i = 0; i < n; i++) {
    a[i] = pairt[i].first;
    b[i] = pairt[i].second;
  }
}
long long pow1(long long n, long long p) {
  if (p == 0) return 1;
  long long x = pow1(n, p / 2);
  x = (x * x) % mod;
  if (p % 2 == 0)
    return x;
  else
    return (x * n) % mod;
}
long long binarySearch(long long arr[], long long l, long long r, long long x) {
  if (r >= l) {
    long long mid = l + (r - l) / 2;
    if (arr[mid] == x) return mid;
    if (arr[mid] > x) return binarySearch(arr, l, mid - 1, x);
    return binarySearch(arr, mid + 1, r, x);
  }
  return -1;
}
bool compare(const pair<long long, long long> &p1,
             const pair<long long, long long> &p2) {
  if (p1.first < p2.first) return true;
  if (p1.first == p2.first) return p1.second < p2.second;
  return false;
}
bool sortbysec(const pair<long long, long long> &a,
               const pair<long long, long long> &b) {
  return (a.second < b.second);
}
long long gcd(long long a, long long b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
long long isPrime(long long n) {
  if (n < 2) return 0;
  if (n < 4) return 1;
  if (n % 2 == 0 or n % 3 == 0) return 0;
  for (long long i = 5; i * i <= n; i += 6)
    if (n % i == 0 or n % (i + 2) == 0) return 0;
  return 1;
}
long long C(long long n, long long r) {
  if (r > n - r) r = n - r;
  long long ans = 1;
  for (long long i = 1; i <= r; i++) {
    ans *= n - r + i;
    ans /= i;
  }
  return ans;
}
long long modexpo(long long x, long long p) {
  long long res = 1;
  x = x % mod;
  while (p) {
    if (p % 2) res = res * x;
    p >>= 1;
    x = x * x % mod;
    res %= mod;
  }
  return res;
}
long long r = 998244353;
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  ;
  long long n, m, l, r;
  cin >> n >> m >> l >> r;
  long long e = 0, o = 0;
  if (l % 2 == 0 && r % 2 == 0) {
    e = (r - l + 2) / 2;
    o = e - 1;
  } else if (l % 2 != 0 && r % 2 != 0) {
    o = (r - l + 2) / 2;
    e = o - 1;
  } else {
    e = (r - l + 1) / 2;
    o = (r - l + 1) / 2;
  }
  if (l == 1 && r == 1)
    cout << 1 << "\n";
  else if (n * m % 2 != 0)
    cout << pow1(r - l + 1, n * m) << "\n";
  else {
    long long p = pow1((e + o) % mod, n * m) % mod;
    long long q = pow1((e - o + mod) % mod, n * m) % mod;
    p = (p + q) % mod;
    p *= pow1(2, mod - 2);
    p %= mod;
    cout << p << "\n";
  }
  return 0;
}
