#include<bits/stdc++.h>
using namespace std;
int a[5010],f[5010][5010],ans,n;
int main(){
    freopen("charger.in","r",stdin);
    freopen("charger.out","w",stdout);
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    for(int i=1;i<=n;i++){
        if(f[a[i]][i]==0){
            for(int j=i;j<=n;j++){
                f[a[i]][j]=f[a[i]][j-1];
                if(a[j]==a[i]){
                    f[a[i]][j]++;
                }
            }
        }
    }
    for(int i=1;i<=n;i++){
        
        for(int j=i+1;j<=n;j++){
            if(f[a[i]][j]-f[a[i]][i-1]==1&&f[a[j]][j]-f[a[j]][i-1]==1){
                ans++;
            }
        }
    }
    cout<<ans;
    return 0;
}