为啥第三个wa了

using namespace std;
int main()
{
    int n ,k;
    cin >> n >> k;
    int x=0,y=0,ans=n;
    do
    {
        x = (n+y) / k;
        y = n % k;
        ans += x;
        n = x;
    }while(x);
    cout << ans;
}