bool IsGeomProgr(int A, int B, int C)
{
    if (A < B || B <= 0 || C <= 0) return false;
    
    if (A == B) return true;
    
    if (A % B != 0) return false;
    
    int ratio = A / B;
    int power = 1;
    
    for (int i = 0; i < 100; i++)
    {
        if (power == ratio) return true;
        if (power > ratio) return false;
        power *= C;
    }
    
    return false;
}