#include<bits/stdc++.h>
#define ll long long 
using namespace std;
string s;
ll ans=1e18;
ll q[101];
void solve()
{
    cin>>s;
    ll n=s.length();
    for(int i=1;i<=n;i++)
    {
        q[i]=q[i-1]+(s[i]=='1');
    }
    if(q[n]==0)
    {
        cout<<0;
        return;
    }
    for(int i=1;i<=n;i++)
    {
        for(int j=i;j<=n;j++)
        {
            ll len=j-i+1;
            ans=min(ans,len-(q[j]-q[i-1])+q[n]-(q[j]-q[i-1]));
        }
    }
    cout<<ans;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    ll T = 1;
    // cin >> T;
    while(T--)
    {
        solve();
    }
    return 0;
}