#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 100;
vector<int> v;
vector<int> vp;
int a[N][20], f[N], invf[N];
int n, p, l, r;
bool vis[N];
int qpow(int x, int b) {
  long long sum = 1;
  long long now = x;
  while (b) {
    if (b & 1) sum = sum * now % p;
    now = now * now % p;
    b >>= 1;
  }
  return sum;
}
void init() {
  vis[1] = true;
  for (int i = 1; i < N; i++) {
    if (vis[i] == false) v.push_back(i);
    for (int j = 0; j < v.size() && i * v[j] < N; j++) {
      vis[i * v[j]] = true;
      if (i % v[j] == 0) break;
    }
  }
  int t = p;
  for (int i = 0; i < v.size(); i++) {
    if (t % v[i] == 0) {
      vp.push_back(v[i]);
      while (t % v[i] == 0) t /= v[i];
    }
  }
  if (t != 1) vp.push_back(t);
  int phi = p;
  for (int i = 0; i < vp.size(); i++) phi = phi / vp[i] * (vp[i] - 1);
  f[0] = invf[0] = 1;
  for (int i = 1; i <= n; i++) {
    int x = i;
    for (int j = 0; j < vp.size(); j++) {
      a[i][j] = a[i - 1][j];
      while (x % vp[j] == 0) a[i][j]++, x /= vp[j];
    }
    f[i] = 1LL * f[i - 1] * x % p;
    invf[i] = qpow(f[i], phi - 1);
  }
}
int calc(int n, int x) {
  if (x < 0) return 0;
  int ret = 1LL * f[n] * invf[x] % p * invf[n - x] % p;
  for (int i = 0; i < vp.size(); i++) {
    ret = 1LL * ret * qpow(vp[i], a[n][i] - a[x][i] - a[n - x][i]) % p;
  }
  return ret;
}
int main() {
  scanf("%d %d %d %d", &n, &p, &l, &r);
  init();
  int ans = 0;
  for (int i = 0; i <= n - l; i++) {
    int nn = n - i;
    ans = (ans +
           1LL * (calc(nn, nn - l >> 1) - calc(nn, nn - min(n, r) - 1 >> 1)) *
               calc(n, i)) %
          p;
  }
  printf("%d\n", ans);
  return 0;
}
