// Slower C++ solution:
#include<bits/stdc++.h>

using namespace std;

#include<ext/pb_ds/assoc_container.hpp>

#include<ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;

#define ordered_set             tree<long long int, null_type, less<long long int>, rb_tree_tag, tree_order_statistics_node_update>

#define LCM(a,b)                (a / __gcd(a,b) ) *b

#define GCD(a,b)                __gcd(a,b)

#define dist(x1,y1,x2,y2)       sqrt((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1))

#define distl(x1,y1,x2,y2)      sqrtl((x2-x1)*(x2-x1) + (y2-y1)*(y2-y1))

#define SQR(a)                  ((a)*(a))

#define fRead(x)                freopen(x,"r",stdin)

#define fWrite(x)               freopen (x,"w",stdout)

#define pb                      push_back

#define mk                      make_pair

#define ff                      first

#define ss                      second

#define lb                      lower_bound

#define ub                      upper_bound

#define all(a)                  a.begin(),a.end()

#define lla(A)                  A.rbegin(), A.rend()

#define Unique(a)               sort(all(a)),a.erase(unique(all(a)),a.end())

#define lastEle(v)              v[v.size()-1]

#define ABS(x)                  ((x)<0?-(x):(x))

#define min3(a,b,c)             min(a,min(b,c))

#define min4(a,b,c,d)           min(a,min(b,min(c,d)))

#define max3(a,b,c)             max(a,max(b,c))

#define max4(a,b,c,d)           max(a,max(b,max(c,d)))

#define max5(a,b,c,d,e)         max(max3(a,b,c),max(d,e))

#define min5(a,b,c,d,e)         min(min3(a,b,c),min(d,e))

#define MEM(a,x)                memset(a,x,sizeof(a))

#define Godspeed                ios_base::sync_with_stdio(0);cin.tie(NULL)

#define urs(r...)               typename decay<decltype(r)>::type

#define FOR(i,a,b)              for(urs(b) i=a;i<=b;i++)

#define ROF(i,a,b)              for(urs(b) i=a;i>=b;i--)

#define REP(i,b)                for(urs(b) i=0;i<b;i++)

#define rep(i, begin, end)      for (__typeof(end) i = (begin) - ((begin) > (end)); i != (end) - ((begin) > (end)); i += 1 - 2 * ((begin) > (end)))

#define PER(i,a,b)              for(urs(b) i=a;i>b;i--)

#define FOREACH(i,t)            for (__typeof(t.begin()) i=t.begin(); i!=t.end(); i++)

#define PRESENT(c,x)            ((c).find(x) != (c).end())

#define CPRESENT(c,x)           (find(all(c),x) != (c).end())

#define SPRESENT(c,x)           ((c).find(x) != string::npos)

#define Lower_bound(v, x)       distance(v.begin(), lower_bound(v.begin(), v.end(), x))

#define Upper_bound(v, x)       distance(v.begin(), upper_bound(v.begin(), v.end(), x))

#define Bye                     return 0

#define SORT(v)                 sort(v.begin(),v.end())

#define revsort(a,n)            sort(a,a+n); reverse(a,a+n)

#define ODD(x)                  (bool)(x&1)

#define Debug                   cout<<endl<<"I AM BATMAN"<<endl;

#define what_is(x)              cerr << __LINE__ <<": " << #x << " is " << x << endl;

#define bin_least_sig_onebit(x) __builtin_ffs(x)

#define bin_leading_zeros(x)    __builtin_clz(x)

#define bin_trailing_zeros(x)   __builtin_ctz(x)

#define bin_total_ones(x)       __builtin_popcount(x)

#define getbit(n,i)             (((n)&(1<<(i)))!=0)

#define setbit0(n,i)            ((n)&(~(1<<(i))))

#define setbit1(n,i)            ((n)|(1<<(i)))

#define togglebit(n,i)          ((n)^(1<<(i)))

#define TIME                    (chrono::steady_clock::now().time_since_epoch().count())

//Datatypes

#define ll                      long long

#define ULL                     unsigned long long

#define LD                      long double

#define UI                      unsigned int

#define US                      unsigned short

#define endl                   '\n'

const long long int MOD = 1000000007; // 998244353

const ll INF = 1e18;

const ll inf = 0xFFFFFFFFFFFFFFFL;

#define PI                      acos(-1.0)

#define EulerGamma              0.57721566490153286060651209

//ll powmod(ll a,ll b)           {ll res=1;a%=mod; assert(b>=0); for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}

ll gcd(ll a, ll b)

{

    return (b?gcd(b,a%b):a);

}

long long int phi(long long int n)

{

    long long int result = 1;

    for (long long int i = 2; i < n; i++)

        if (GCD(i, n) == 1)

            result++;

    return result;

}

long long int Phi(long long int n)

{

    long long int res=n;

    for(long long int i=2; i*i<=n; i++)

    {

        if(!(n%i))

        {

            while(!(n%i))

            {

                n/=i;

            }

            res-=(res/i);

        }

    }

    if(n>1)

    {

        res-=(res/n);

    }

    return res;

}

bool isprime(long long int n)

{

    bool flag = true;

    for(long long int i = 2; i*i <= n; ++i)

        //for(int i = 2; i <= sqrt(n); ++i)

        //for(int i = 2; i <= n/2; ++i)

    {

        if(n%i == 0)

        {

            flag = false;

            break;

        }

    }

    return flag;

}

long long binaryPow(long long a, long long b)

{

    long long ans = 1;

    while(b > 0)

    {

        if(b & 1)

        {

            ans = ans * a ;

        }

        a = a * a ;

        b >>= 1;

    }

    return ans;

}

bool sortbysec(const pair<long long int,long long int> &a, const pair<long long int,long long int> &b)

{

    return (a.second < b.second);

}

ll BMod(ll B,ll P,ll M)

{

    ll R=1;

    B=B%M;

    while(P)

    {

        if(P&1)

            R=(R*B)%M;

        P >>= 1;

        B=(B*B)%M;

    }

    return R;

}

ll invMOD(ll num,ll M)

{

    return BMod(num,M-2,M);

}

ll MulMod(ll a, ll b, ll m)

{

    ll result = 0LL;

    a %= m;

    while (b)

    {

        if (b % 2)

            result = (result + a) % m;

        a = (a + a) % m;

        b /= 2LL;

    }

    return result;

}

ll BigMod(ll a,ll b, ll m)

{

    ll result = 1LL;

    a %= m;

    while (b)

    {

        if (b % 2ULL)

            result = MulMod(result, a, m);

        a = MulMod(a, a, m);

        b /= 2LL;

    }

    return result;

}

#ifdef Combi

const ll nSz = 2000006;

ll F[nSz + 1], tMod = MOD;

void Factorial()

{

    F[0] = 1;

    for(ll i = 1; i <= nSz; i++)

        F[i] = (F[i - 1] * i) % tMod;

}

inline ll nCr(ll n, ll r)

{

    return (F[n] * invMOD((F[n - r] * F[r]) % tMod, tMod)) % tMod;

}

ll NCR[51][51];

void precalcCombi()

{

    MEM(NCR,0LL);

    REP(i,51)

    {

        NCR[i][0]=1;

    }

    FOR(i,1,50)

    {

        FOR(j,1,i)

        {

            NCR[i][j]=NCR[i-1][j-1]+NCR[i-1][j];

        }

    }

}

#endif

long long pw(long long x, long long p)

{

    if (p == 0)

        return 1;

    if (p == 1)

        return x;

    long long v = pw(x, p / 2);

    v = v * v % MOD;

    if (p % 2 != 0)

        v = v * x % MOD;

    return v;

}

//Debugging stuff

#define error(args...) { string _s = #args; replace(_s.begin(), _s.end(), ',', ' '); stringstream _ss(_s); istream_iterator<string> _it(_ss); err(_it, args); }

void err(istream_iterator<string> it) {}

template<typename T, typename... Args>

void err(istream_iterator<string> it, T a, Args... args)

{

    cerr << *it << " = " << a << endl;

    err(++it, args...);

}

#define pii pair<int,int>

#define pll pair<long long,long long>

#define pdd pair<double,double>

#define pldld pair<long long double, long long double>

// find_by_order(k)  returns iterator to kth element starting from 0;

// order_of_key(k) returns count of elements strictly smaller than k;

/*

    Syed Rifat Raiyan

    IUT CSE-18

    Go Beyond! Plus Ultra!

*/



int main()

{

    Godspeed;

    int Tests=1;

    //cin>>Tests;

    while(Tests--)

    {

        ll n;

        cin>>n;

        vector<ll>p(n),p2(n);

        REP(i,n)

        {

            cin>>p[i];

            p2[i]=p[i];

        }

        sort(all(p2));

        ll mismatches=0;

        REP(i,n)

        {

            if(p[i]!=p2[i])

            {

                mismatches++;

            }

        }

        if(mismatches<=2)

        {

            cout<<"YES"<<endl;

        }

        else

        {

            cout<<"NO"<<endl;

        }

    }

    Bye;

}


// Faster C++ solution for the same problem (measured speedup: 5.353117638478121x):
#include<stdio.h>



int main()

{

    int i,j,a[60],b[60],n,flag;



    scanf("%d",&n);



    for(i=0;i<n;i++)

    {

        scanf("%d",&a[i]);

    }



    for(i=0,j=1;i<n;i++,j++)

    {

        b[i] = j;

    }



    for(i=0,flag=0;i<n;i++)

    {

        if(a[i]!=b[i])

            flag++;

    }



    if(flag<=2)

        printf("YES");

    else

        printf("NO");



    return 0;

}