#include <iostream>
#include <fstream>
using namespace std;

int b, n, perechi[1000000][2];

int main() {
    ifstream fin("armonica.in");
    ofstream fout("armonica.out");
    fin >> b;
    for (int a = 1; a <= b; ++a) {
        int c = 1;
        while ((long long)2 * a * c < (long long)b * (a + c)) {
            ++c;
        }
        if (b == 2 * a * c / (a + c)) {
            perechi[n][0] = a;
            perechi[n++][1] = c;
            if (a != c) {
                perechi[n][0] = c;
                perechi[n++][1] = a;
            }
        }
    }
    cout << n << endl;
    for (int i = 0; i < n; ++i) {
        cout << perechi[i][0] << ' ' << perechi[i][1] << endl;
    }
    return 0;
}