easy

#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;

int main(){
    int n;
    cin>>n;
    vector<int> arr(n+1),gcds;
    for (int i=1;i<=n;i++) cin>>arr[i];
    for (int i=1;i<n;++i){
        for(int j=i+1;j<=n;j++){
            gcds.push_back(arr[i]*arr[j]/__gcd(arr[i],arr[j]));
        }
    }
    sort(gcds.begin(),gcds.end(),greater<int>());
    cout<<gcds.front();
    return 0;
}