ffml\

#include <iostream>
#include <cstring>

using namespace std;

int main()
{
    /// Varianta 52
    /// I.2)
    /*
    int n, i, x, c = 0, d = 0;
    cin >> n;
    for(i = 1; i <= n; i++)
    {
        cin >> x;
        while(!(x % 2))
        {
            x /= 2;
            d++;
        }
        while(!(x % 5))
        {
            x /= 5;
            c++;
        }
    }
    if(c < d)
        cout << c << "\n";
    else cout << d << "\n";
    */

    /// II.5)
    /*
    int n, i, j, nr = 0, f;
    char s[30];
    cin >> n;
    for(i = 0; i <= n; i++)
    {
        cin.getline(s, 30);
        f = 1;
        for(j = 0; (s[j] != NULL) && f; j++)
            if(strchr("aeiou", s[j]) == NULL)
                f = 0;
        if(f)
            nr++;
    }
    cout << nr-1;
    */

    /// III.4)
    int n, k;
    cin >> n >> k;
    if((n - (k * (k-1))/2) % k == 0)
        return (n - (k * (k-1))/2) / k;
    cout << "Nu exista.";
    return 0;
}