int main() {
    const int N = 2;
    int base = 10;
    int c1 = 0;
    int c2 = 0;
    int k;

    for (k = 1; k < pow(base, N); k++) {
        c1++;
        if (k % (base - 1) == (k * k) % (base - 1)) {
            c2++;
            printf(, k);
        }
    }

    printf(, c2, c1, 100.0 - 100.0 * c2 / c1);
    return 0;
}