#include <iostream>

using namespace std;
int main(){
    int n,a,b,c; cin >> n >> a >> b >> c;
    if(a<b){
        if(a<c) cout << "Yes\n";
        else cout << "No\n"; 
    }else{
        if(c<a) cout << "Yes\n";
        else cout << "No\n";
    }
}