P2837

#include<bits/stdc++.h>
#include<cmath> 
using namespace std;
typedef int ll;
ll n,t,b[10010],minn=99999;
int main(){
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>t;
        b[i]=b[i-1]+t;
    }
    for(int i=0;i<=n;i++){
        int sum=0,t1=0,t2=0;
        t1=b[i]-i;
        sum+=t1;
        t2=b[n]-b[i];
        t2=(n-i)*2-t2;
        sum+=t2;
        minn=min(sum,minn);
    }
    cout<<minn;
    
    return 0;
}