#include<algorithm>
#include<iostream>
#include<vector>
using namespace std;
typedef long long lint;
typedef vector<int>vi;
typedef pair<int,int>pii;
#define rep(i,n)for(int i=0;i<(int)(n);++i)

// https://yukicoder.me/problems/3422

#define N 50000
int n;
int c[N];

void f(){
  cout<<"No"<<endl;
  exit(0);
}

bool kado(int i){
  if(i<=0||i>=n-1)return 1;
  if(c[i+1]==c[i-1])return 0;
  return (c[i]-c[i+1])*(c[i]-c[i-1])>0;
}

int main(){
  cin>>n;
  rep(i,n)cin>>c[i];
  vi a;
  rep(i,n-2){
    if(!kado(i+1)){
      rep(j,5)a.push_back(i+j-1);
    }
  }
  if(a.size()>=200)f();
  for(int b:a){
    rep(i,n){
      if(b==i)continue;
      swap(c[i],c[b]);
      vi tt(a);
      rep(j,5)tt.push_back(i+j-2);
      rep(j,5)tt.push_back(b+j-2);
      int ok=1;
      for(int t:tt)if(!kado(t)){ok=0;break;}
      if(ok){cout<<"Yes"<<endl;return 0;}
      swap(c[i],c[b]);
    }
  }
  f();
}