#include <iostream>
#include <string>
#include <algorithm>

using namespace std;

int main() {
    int ans = 0, x = 0;
    std::string s;
    getline(std::cin, s);
    for (uint8_t byte : s) {
        if (x != 0) {
            x--;
        } else {
            ans++;
            for (int i = 7; i >= 0; --i) {
                if ((byte & (1 << i)) != 0) {
                    x++;
                } else {
                    break;
                }
            }
            x = max(0, x - 1);
        }
    }
    cout << ans;
}