#include <cstdio>

#include <cstring>

#include <iostream>

#include <algorithm>

using namespace std;

#define maxn 200005

int n,ai[maxn],bi[maxn],ans;

inline void in(int &now)

{

    int if_z=;now=;

    char Cget=getchar();

    while(Cget>''||Cget<'')

    {

        if(Cget=='-') if_z=-;

        Cget=getchar();

    }

    while(Cget>=''&&Cget<='')

    {

        now=now*+Cget-'';

        Cget=getchar();

    }

    now*=if_z;

}

bool cmp(int a,int b)

{

    return a<b;

}

int main()

{

    in(n);

    for(int i=;i<=n;i++) in(ai[i]),bi[i]=ai[i];

    sort(ai+,ai+n+,cmp);

    for(int i=;i<=n;i++) if(ai[i]!=bi[i]) ans++;

    if(ans<=) cout<<"YES";

    else cout<<"NO";

    return ;

}