#include<cstdio>
#include<unordered_map>
#define N 20
#define ll long long
using namespace std;
int n,ans;ll t[N],a[N];
unordered_map<ll,bool>mp;
int swap(int &x,int &y){int t=x;x=y;y=t;}
void dfs()
{
    ans++;
    ll sum=0,x;
    for(int i=0;i<n;i++)sum+=a[i]*t[i];
    for(int i=0;i<n-1;i++)
        for(int j=i+1;j<n;j++)
            if(a[i]>a[j])
            {
                x=sum+(a[i]-a[j])*(t[j]-t[i]);
                if(mp[x])continue;
                mp[x]=1;
                swap(a[i],a[j]);
                dfs();
                swap(a[i],a[j]);
            }
}
int read(){
    int sum=0;bool f=0;char c=getchar();
    for(;c<48||c>57;c=getchar())if(c==45)f=1;
    for(;c>=48&&c<=57;c=getchar())sum=sum*10+(c&15);
    return f?-sum:sum;
}
int main(){
    freopen("changgao_perm.in","r",stdin);freopen("changgao_perm.out","w",stdout);
    t[0]=1;for(int i=1;i<N;i++)t[i]=t[i-1]*10;
    n=read();for(int i=0;i<n;i++)a[i]=read();
    dfs();
    printf("%d",ans);
    return 0;
}