#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>
#include <queue>
#include <map>
#include <cmath>
#include <iomanip>
#include <set>
#include <cstdio>
#include <string>

using namespace std;

int main() {
  cin.tie(0);
  ios::sync_with_stdio(false);
  cout << fixed << setprecision(15);
  int n;
  cin >> n;
  vector<int> x(3, 0);
  for (int i = 0; i < 3; i++) {
    cin >> x[i];
  }
  if (x[0] == 1 && x[n - 1] == n || x[0] == n && x[n - 1] == n) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
  return 0;
}