//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using db = double;
using ld = long double;
template<typename T> using V = vector<T>;
template<typename T> using VV = vector<vector<T>>;
#define fs first
#define sc second
#define pb push_back
#define mp make_pair
#define mt make_tuple
#define eb emplace_back
#define lb lower_bound
#define ub upper_bound
#define all(v) (v).begin(),(v).end()
#define siz(v) (ll)(v).size()
#define rep(i,a,n) for(ll i=a;i<(ll)(n);++i)
#define repr(i,a,n) for(ll i=n-1;(ll)a<=i;--i)
#define ENDL '\n'
typedef pair<int,int> Pi;
typedef pair<ll,ll> PL;
constexpr ll mod = 1000000007;
constexpr ll INF = 1000000099;
constexpr ll LINF = (ll)(1e18 +99);
const vector<ll> dx={-1,1,0,0},dy={0,0,-1,1};
template<typename T,typename U> inline bool chmin(T& t, const U& u){if(t>u){t=u;return 1;}return 0;}
template<typename T,typename U> inline bool chmax(T& t, const U& u){if(t<u){t=u;return 1;}return 0;}
template<typename T> inline T gcd(T a,T b){return b?gcd(b,a%b):a;}

template<typename T,typename Y> inline T mpow(T a, Y n) {
  T res = 1;
  for(;n;n>>=1) {
    if (n & 1) res = res * a;
    a = a * a;
  }
  return res;
}

template<typename T,typename Y>
ostream& operator<<(ostream& os,const pair<T,Y>& p){
   return os<<"{"<<p.fs<<","<<p.sc<<"}";
}
template<typename T> ostream& operator<<(ostream& os,const V<T>& v){
   os<<"{";
  for(auto e:v)os<<e<<",";
  return os<<"}";
}
template<typename ...Args>
void debug(Args&... args){
  for(auto const& x:{args...}){
    cerr<<x<<' ';
  }
  cerr<<ENDL;
}



signed main(){
  cin.tie(0);cerr.tie(0);ios::sync_with_stdio(false);
  cout<<fixed<<setprecision(20);
  string s;cin>>s;
  int n=siz(s);
  ll ans=0,ocnt=0,od0=0;
  set<PL> se;

  rep(i,0,n){
    if(s[i]=='1'){
      ans+=(++ocnt+1)/2;
      se.emplace(i,1);
    }
  }

  ll tmp=(ocnt%2)^1,bac=(ocnt+1)/2,cnt=0;
  rep(i,0,n){
    if(s[i]=='1'){
      cnt++;
      continue;
    }

    if(cnt%2){
      bac+=tmp;
      ans+=bac;
      tmp^=1;
      ++cnt;
      se.emplace(i,0);
    }else{
      ++od0;
    }
  }

  ll now=0;
  cnt=0;
  rep(i,0,n){
    if(s[i]=='0'){
      if((*se.lb({i,-1})).fs!=i){
        cnt++;
      }else{
        now++;
      }
    }else{
      if(now%2==0){
        ans+=(od0-cnt)+(cnt/2);
      }else{
        ans+=(cnt+1)/2;
      }
      ++now;
    }
  }
  cout<<ans<<ENDL;

}
//! ( . _ . ) ! 
//CHECK overflow,vector_size,what to output?