#include <bits/stdc++.h>
using namespace std;
const int P = 10, N = 1e5 + 10;
int inverse(int a, int m) {
  if (a <= 1) return a;
  int ans = (1 - (long long int)inverse(m % a, a) * m) / a;
  if (ans < 0) ans += m;
  return ans;
}
int fact[N], ifact[N], pot[N][P];
vector<int> primes(int n) {
  vector<int> ans;
  for (int d = 2; d * d <= n; d++)
    if (n % d == 0) {
      ans.push_back(d);
      while (n % d == 0) {
        n /= d;
      }
    }
  if (n > 1) ans.push_back(n);
  return ans;
}
int mod;
vector<int> p;
int expomod(long long int a, long long int e) {
  int ans = 1;
  while (e) {
    if (e & 1) ans = ans * a % mod;
    e /= 2;
    a = a * a % mod;
  }
  return ans;
}
int comb(int m, int n) {
  int ans = (long long int)fact[m] * ifact[n] % mod * ifact[m - n] % mod;
  for (int i = 0; i < (int)(((int)(p).size())); i++) {
    int pp = pot[m][i] - pot[n][i] - pot[m - n][i];
    if (pp) ans = (long long int)ans * expomod(p[i], pp) % mod;
  }
  return ans;
}
int go(int n, int bal) {
  long long int ans = 0;
  for (int x = 0, y = bal; x + y <= n; x++, y++) {
    ans += (long long int)comb(n, x) * comb(n - x, y) % mod;
    if (ans >= mod) ans -= mod;
  }
  return ans;
}
int main() {
  int n, l, r;
  cin >> n >> mod >> l >> r;
  p = primes(mod);
  fact[0] = ifact[0] = 1;
  int fn = 1;
  for (int i = 1; i <= n; i++) {
    int d = -1;
    for (int j = 0; j < (int)(((int)(p).size())); j++)
      if (i % p[j] == 0) {
        d = j;
        break;
      }
    if (d == -1)
      fact[i] = i;
    else {
      fact[i] = fact[i / p[d]];
      for (int j = 0; j < (int)(((int)(p).size())); j++)
        pot[i][j] = pot[i / p[d]][j] + (j == d);
    }
    fn = (long long int)fn * fact[i] % mod;
  }
  ifact[n] = inverse(fn, mod);
  for (int i = n - 1; i >= 0; i--)
    ifact[i] = (long long int)ifact[i + 1] * fact[i + 1] % mod;
  for (int i = 1; i <= n; i++) {
    fact[i] = (long long int)fact[i - 1] * fact[i] % mod;
    for (int j = 0; j < (int)(((int)(p).size())); j++)
      pot[i][j] += pot[i - 1][j];
  }
  long long int ans = 0;
  for (int i = 0; i < (int)(2); i++) {
    ans += go(n, l + i);
    ans -= go(n, r + 1 + i);
  }
  ans %= mod;
  if (ans < 0) ans += mod;
  cout << ans << endl;
  return 0;
}
