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#include <bits/stdc++.h>
using namespace std;

const int MAXN = 1e5+5;
bool dp[MAXN];
int t[MAXN],fale[MAXN];
vector<int> divisor[MAXN];

void sieve(int n){
    for(int i=2;i<=n;i++){
        for(int j=2;i*j<=n;j++) divisor[i*j].push_back(i);
    }
}


bool check(int x, int n){
    int sum=0;
    for(int i=1;i<=n;i++){
        if(i>x) sum -= fale[i-x];
        if(sum > t[i] || (i > n-x+1 && sum != t[i])) return false;
        fale[i] = t[i] - sum;
        sum = t[i];
    }
    return true;
}

int32_t main(){
    int n; cin >> n;
    sieve(n);
    for(int i=1;i<=n;i++) cin >> t[i];
    int ans=1;
    for(int i=2;i<=n;i++){
        bool cont = true;
        for(int d: divisor[i]) cont &= dp[d];
        if(!cont) dp[i] = false;
        else dp[i] = check(i,n);
        ans = max(ans,i * dp[i]);
    }
    cout << ans;
}