nroot

long long nroot(int n,long long x)
{
    if(x<0)
        x=-x;
    else
        if(x==0)
            return 0;
    double m,st=0,dr=x+0.01;
    while(dr-st>0.01)
    {
        m=(st+dr)/2;
        if(pow(m,n)>x)
            dr=m;
        else
            st=m;
    }
    return (long long) dr;
}