#include <bits/stdc++.h> #define int long long using namespace std; int n, a[30005], s[30005], t[30005]; int ans=INT_MAX; signed main() { scanf("%d", &n); for (int i=1; i<=n; i++) { scanf("%d", &a[i]); if (a[i] == 1) a[i] = 0; else a[i] = 1; s[i] = s[i-1] + a[i]; t[i] = t[i-1] + (1-a[i]); } for (int i=1; i<=n; i++) { int cur = s[i] + t[n]-t[i]; ans = min(ans, cur); } printf("%d", ans); return 0; }