LL work(LL x)
{
    LL res = x;

    for(int i = 2; i <= sqrt(x); i ++ )
        if(x % i == 0)
        {
            res = res / i * (i-1);
            while(x % i == 0) x/=i;
        }

    if(x>1) res = res / x * (x-1);

    return res;
}