#include <bits/stdc++.h>
using namespace std;
template <class T>
void _R(T &x) {
  cin >> x;
}
void _R(int &x) { scanf("%d", &x); }
void _R(int64_t &x) { scanf("%lld", &x); }
void _R(double &x) { scanf("%lf", &x); }
void _R(char &x) { scanf(" %c", &x); }
void _R(char *x) { scanf("%s", x); }
void R() {}
template <class T, class... U>
void R(T &head, U &...tail) {
  _R(head);
  R(tail...);
}
template <class T>
void _W(const T &x) {
  cout << x;
}
void _W(const int &x) { printf("%d", x); }
void _W(const int64_t &x) { printf("%lld", x); }
void _W(const double &x) { printf("%.16f", x); }
void _W(const char &x) { putchar(x); }
void _W(const char *x) { printf("%s", x); }
template <class T, class U>
void _W(const pair<T, U> &x) {
  _W(x.first);
  putchar(' ');
  _W(x.second);
}
template <class T>
void _W(const vector<T> &x) {
  for (auto i = x.begin(); i != x.end(); _W(*i++))
    if (i != x.cbegin()) putchar(' ');
}
void W() {}
template <class T, class... U>
void W(const T &head, const U &...tail) {
  _W(head);
  putchar(sizeof...(tail) ? ' ' : '\n');
  W(tail...);
}
template <class T, class... U>
void DEBUG(const T &head, const U &...tail) {}
int MOD = 1e9 + 7;
void ADD(int64_t &x, int64_t v) {
  x = (x + v) % MOD;
  if (x < 0) x += MOD;
}
const int SIZE = 1e6 + 10;
struct Combination {
  int a[12], xb, s[SIZE][12], j, jf[SIZE], vf[SIZE], mod;
  void init(int _mod) {
    mod = _mod;
    int x = mod, y = mod;
    for (int i = 2; i * i <= x; ++i)
      if (x % i == 0) {
        a[++xb] = i;
        y = y / i * (i - 1);
        while (x % i == 0) x /= i;
      }
    if (x > 1) a[++xb] = x, y = y / x * (x - 1);
    *jf = *vf = 1;
    for (int i = (1); i < (SIZE); ++i) {
      for (x = i, memcpy(s[i], s[i - 1], 48), j = 1; j <= xb; ++j)
        if (x % a[j] == 0)
          while (x % a[j] == 0) x /= a[j], ++s[i][j];
      jf[i] = 1ll * jf[i - 1] * x % mod;
      vf[i] = 1ll * vf[i - 1] * pow(x, y - 1) % mod;
    }
  }
  int pow(int x, int y) {
    int ans = 1;
    for (; y; y >>= 1, x = 1ll * x * x % mod)
      if (y & 1) ans = 1ll * ans * x % mod;
    return ans;
  }
  int64_t C(int x, int y) {
    int i, ans = 1ll * jf[x] * vf[y] % mod * vf[x - y] % mod;
    for (i = 1; i <= xb; ++i)
      ans = 1ll * ans * pow(a[i], s[x][i] - s[y][i] - s[x - y][i]) % mod;
    return ans;
  }
} cal;
int64_t solve(int n, int x) {
  int64_t v = 0;
  for (int i = (x); i <= (n); ++i) {
    ADD(v, cal.C(n, i) * cal.C(i, (i - x) / 2));
  }
  return v;
}
int main() {
  int n, l, r;
  R(n, MOD, l, r);
  cal.init(MOD);
  int64_t an = solve(n, l);
  ADD(an, -solve(n, r + 1));
  W(an);
  return 0;
}
