#include <iostream>
#include <vector>
int main() {
std::vector<int> people;
for (int i = 1; i <= 21; i++) {
people.push_back(i);
}
int count = 0;
while (people.size() > 1) {
for (size_t i = 0; i < people.size(); i++) {
count++;
if (count % 5 == 0) {
people.erase(people.begin() + i);
i--;
}
}
}
std::cout << people[0] << std::endl;
return 0;
}