#include<bits/stdc++.h>

using namespace std;

typedef long long ll;

const ll INF=1e18+;

const ll N=1E6+;

ll arr[N];

ll n;

ll cal(ll x){

    ll sum=,s=;

    for(ll i=;i<=n;i++){

        s=(s+arr[i])%x;

        sum+=min(s,x-s);

    }

    return sum;

}

int main(){

    ios::sync_with_stdio();

    cin>>n;

    ll cnt=;

    for(ll i=;i<=n;i++){

        cin>>arr[i];

        cnt+=arr[i];

    }

    if(cnt==){

        cout<<-<<endl;

        return ;

    }

    if(n==){

        cout<<<<endl;

        return ;

    }

    ll m=sqrt(cnt);

    ll sum=INF;

    for(ll i=;i<=m;i++){

        if(cnt%i==){

            sum=min(sum,cal(i));

            while(cnt%i==) cnt/=i;

        }

    }

    if(cnt!=) sum=min(sum,cal(cnt));

    cout<<sum<<endl;

    return ;

}