#include <bits/stdc++.h>

using namespace std;

using i32 = int32_t;
using i64 = long long;
using ldb = long double;

const i32 inf = INT_MAX / 2;
const i64 INF = LLONG_MAX / 2;

#define int i64

using vi = vector<int>;


i32 main() {
    ios::sync_with_stdio(false), cin.tie(nullptr);
    string s;
    cin >> s;
    int n = s.size();
    vi a(n + 1);
    for (int i = 1; i <= n; i++)
        a[i] = a[i - 1] + s[i - 1] - '0';
    int res = a[n];
    for (int l = 1, val; l <= n; l++)
        for (int r = l; r <= n; r++) {
            val = a[n] - 2 * (a[r] - a[l - 1]) + r - l + 1;
            res = min(res, val);
        }
    cout << res;
    return 0;
}