#include <bits/stdc++.h>
using namespace std;
const long long size = 1e5 + 5;
long long n, p, l, r;
long long tot;
long long prime[45];
long long fac[size], inv[size];
long long tim[size][45];
long long quick_pow(long long a, long long b) {
  long long ans = 1;
  while (b) {
    if (b & 1) ans = ans * a % p;
    a = a * a % p;
    b >>= 1;
  }
  return ans;
}
long long phi(long long n) {
  long long res = n;
  for (long long i = 2; i * i <= n; i++) {
    if (n % i == 0) {
      res = res - res / i;
      do n /= i;
      while (n % i == 0);
    }
  }
  if (n > 1) res = res - res / n;
  return res;
}
void init() {
  long long temp = p;
  for (long long i = 2; i * i <= temp; i++) {
    if (temp % i == 0) {
      prime[tot++] = i;
      do temp /= i;
      while (temp % i == 0);
    }
  }
  if (temp > 1) prime[tot++] = temp;
  fac[0] = fac[1] = 1;
  inv[0] = inv[1] = 1;
  long long phip = phi(p);
  memset(tim, 0, sizeof(tim));
  for (long long i = 2; i <= n; i++) {
    long long x = i;
    for (long long j = 0; j < tot; j++) {
      tim[i][j] = tim[i - 1][j];
      while (x % prime[j] == 0) x /= prime[j], tim[i][j]++;
    }
    fac[i] = fac[i - 1] * x % p;
    inv[i] = quick_pow(fac[i], phip - 1);
  }
}
long long combi(long long n, long long m) {
  if (m > n) return 0;
  if (m < 0) return 0;
  if (m == 0) return 1;
  long long ans = (fac[n] * inv[n - m] % p) * inv[m] % p;
  for (long long i = 0; i < tot; i++) {
    ans = ans * quick_pow(prime[i], tim[n][i] - tim[n - m][i] - tim[m][i]) % p;
  }
  return ans;
}
signed main() {
  scanf("%lld%lld%lld%lld", &n, &p, &l, &r);
  long long ans = 0;
  init();
  for (long long i = 0; i <= n; i++) {
    long long m = n - i;
    ans = (ans + combi(n, i) * ((-combi(m, (m + min(r, m)) / 2 + 1) +
                                 combi(m, (m + l + 1) / 2) + p) %
                                p)) %
          p;
  }
  printf("%lld\n", ans);
}
