#include #define rep(i, n) for (int i = 0; i < int(n); i++) #define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--) #define reps(i, n) for (int i = 1; i <= int(n); i++) #define rreps(i, n) for (int i = int(n); i >= 1; i--) #define repc(i, n) for (int i = 0; i <= int(n); i++) #define rrepc(i, n) for (int i = int(n); i >= 0; i--) #define repi(i, a, b) for (int i = int(a); i < int(b); i++) #define repic(i, a, b) for (int i = int(a); i <= int(b); i++) #define each(x, y) for (auto &x : y) #define all(a) (a).begin(), (a).end() #define bit(b) (1ll << (b)) using namespace std; using i32 = int; using i64 = long long; using u64 = unsigned long long; using f80 = long double; using vi32 = vector; using vi64 = vector; using vu64 = vector; using vf80 = vector; using vstr = vector; inline void yes() { cout << "Yes" << '\n'; exit(0); } inline void no() { cout << "No" << '\n'; exit(0); } inline i64 gcd(i64 a, i64 b) { if (min(a, b) == 0) return max(a, b); if (a % b == 0) return b; return gcd(b, a % b); } inline i64 lcm(i64 a, i64 b) { return a / gcd(a, b) * b; } inline u64 xorshift() { static u64 x = 88172645463325252ull; x = x ^ (x << 7); return x = x ^ (x >> 9); } template class pqasc : public priority_queue, greater> {}; template class pqdesc : public priority_queue, less> {}; template inline void amax(T &x, T y) { if (x < y) x = y; } template inline void amin(T &x, T y) { if (x > y) x = y; } template inline T exp(T x, i64 n, T e = 1) { T r = e; while (n > 0) { if (n & 1) r *= x; x *= x; n >>= 1; } return r; } template inline T bis(T ok, T ng, function f, T eps = 1) { while (abs(ok - ng) > eps) { T mi = (ok + ng) / 2; (f(mi) ? ok : ng) = mi; } return ok; } template istream& operator>>(istream &is, vector &v) { each(x, v) is >> x; return is; } template ostream& operator<<(ostream &os, vector &v) { rep(i, v.size()) { if (i) os << ' '; os << v[i]; } return os; } template istream& operator>>(istream &is, pair &p) { is >> p.first >> p.second; return is; } template ostream& operator<<(ostream &os, pair &p) { os << p.first << ' ' << p.second; return os; } void solve(); int main() { ios::sync_with_stdio(0); cin.tie(0); cout << fixed << setprecision(16); solve(); return 0; } int dp[2][200002]; void solve() { string s; cin >> s; reverse(all(s)); s += '0'; int n = s.size(); rep(i, 2) rep(j, 200001) dp[i][j] = 1e9; dp[0][0] = 0; rep(i, n) rep(j, 2) { int x = s[i] - '0'; if (j == 1) { if (x == 1) { amin(dp[1][i + 1], dp[j][i]); } else { amin(dp[0][i + 1], dp[j][i] + 1); amin(dp[1][i + 1], dp[j][i] + 1); } } else { if (x == 1) { amin(dp[0][i + 1], dp[j][i] + 1); amin(dp[1][i + 1], dp[j][i] + 1); } else { amin(dp[0][i + 1], dp[j][i]); } } } cout << min(dp[0][n], dp[1][n]) << endl; }