#include <iostream>
int main() {
    int n{5};
    if (n < 0 || n > 100) {
        std::cout << "invalid\n";
        return 1;
    }
    int count{0};
    for (int i{0}; i < n; ++i) {
        if (i % 2 == 0) {
            ++count;
        }
    }
    std::cout << count << "\n";
    return 0;
}