#include<bits/stdc++.h> using namespace std; #define ALL(x) x.begin(),x.end() #define rep(i,n) for(int i=0;i<(n);i++) #define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl; #define INF 1000000000 #define mod 1000000007 using ll=long long; const ll LINF=1001002003004005006ll; int dx[]={1,0,-1,0}; int dy[]={0,1,0,-1}; ll gcd(ll a,ll b){return b?gcd(b,a%b):a;} template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;} template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;} signed main(){ cin.tie(0); ios::sync_with_stdio(0); string s;cin>>s; reverse(ALL(s)); s.push_back('0'); int n=(int)s.size(); int nxt[n];//nxt0 nxt[n-1]=n-1; for(int i=n-2;i>=0;i--){ nxt[i]=nxt[i+1]; if(s[i]=='0') nxt[i]=i; } ll dp1[n+1],dp2[n+1]; rep(i,n+1)dp1[i]=LINF,dp2[i]=LINF; dp1[0]=0,dp2[0]=0; rep(i,n){ if(s[i]=='0'){ chmin(dp1[i+1],dp1[i]); chmin(dp1[i+1],dp2[i+1]+1); chmin(dp2[i+1],dp2[i]+1); }else{ chmin(dp2[nxt[i]+1],dp1[i]+1); chmin(dp2[nxt[i]+1],dp2[i]+1); chmin(dp1[i+1],dp1[i]+1); } } // cout<<" ";for(auto c:s) cout<<c<<" ";cout<<endl; // rep(i,n+1){if(dp1[i]==LINF)cout<<"I";else cout<<dp1[i];cout<<" ";}cout<<endl; // rep(i,n+1){if(dp2[i]==LINF)cout<<"I";else cout<<dp2[i];cout<<" ";}cout<<endl; cout<<dp1[n]<<endl; return 0; }