What is test number 3 ?

#include <iostream>
#include <cmath>
using namespace std;
typedef unsigned short ushort;

ushort POWER(ushort x, ushort y)
{
    ushort z=x;
    for (ushort i=1; i<y; i++)
        x = x*z;
    if (y==0)
        return 1;
    else
        return x;
}

int main()
{
    ushort n,m,y;
    bool t=false;
    cin >> n >> m >> y;
    for (ushort i=0; i<=(m-1); i++)
        if ((POWER(i,n)%m)==y)
        {
            cout << i << " ";
            t = true;
        }
    if (!t)
        cout << "-1";
    return 0;
}

If I use type on "int", then TEST #4 ...