05. Sort Numbers

#include <iostream>
#include <sstream>
#include <string>
#include <set>

using namespace std;

int main() {
    string line;
    getline(cin, line);

    istringstream ss(line);

    set<int> numbers;

    int number;

    while (ss >> number) {
        numbers.insert(number);
    }

    while (!numbers.empty()) {
        cout << *numbers.begin();
        numbers.erase(numbers.begin());
        if (!numbers.empty()) {
            cout << " <= ";
        }
    }

    cout << endl;
    return 0;
}