#include<bits/stdc++.h>
using namespace std;
int dp1[30005] , dp2[30005] , n , a[30005] , minn = 1e9;
int main(){
    cin >> n;
    for(int i = 1;i <= n;i++){
    	cin >> a[i];
    	dp1[i] = dp1[i - 1];
    	dp2[i] = dp2[i - 1];
    	if(a[i] == 1)dp1[i]++;
    	else dp2[i]++;
	}
	for(int i = 1;i <= n + 1;i++){
		int l = min(dp1[i - 1] , dp2[i - 1]) , r = min(dp1[n] - dp1[i - 1] , dp2[n] - dp2[i - 1]);
		minn = min(minn , l + r);
	}
	cout << minn;
    return 0;
}