#include <iostream>

using namespace std;
void rec(int i) {
    if(i == 51) {
        return;
    }
    rec(i + 1);
    if(i % 2 == 0) {
        cout << i << " ";
    }
}
int main()
{
    rec(1);
    return 0;
}
/*
 rec(1)
 rec(2) --> cout << 2 << endl;
 rec(3)
 rec(4) --> cout << 4 << endl;
 rec(5)
 rec(6) --> cout << 6 << endl;
 rec(7)
 rec(8) --> cout << 8 << endl;
 rec(9)
 rec(10) --> cout << 10 << endl;
 rec(11)
 **/