#include<iostream> using namespace std; int n,zui1[30005],zui2[30005],org[30005],minn=10000000; int main() { cin>>n; for(int i=1;i<=n;i++) { cin>>org[i]; } for(int i=1;i<=n;i++) { zui1[i]+=zui1[i-1]; if(org[i-1]==2) zui1[i]++; } for(int i=n;i>=1;i--) { zui2[i]+=zui2[i+1]; if(org[i+1]==1) zui2[i]++; } for(int i=1;i<=n;i++) { if(zui1[i]+zui2[i]<minn) minn=zui1[i]+zui2[i]; } cout<<minn; }