ll random(ll n){    return (ll)((double)rand()/RAND_MAX*n + 0.5);}ll pow_mod(ll a,ll p,ll n){    if(p == 0)        return 1;    ll ans = pow_mod(a,p/2,n);    ans = ans*ans%n;    if(p%2)        ans = ans*a%n;    return ans;}bool Witness(ll a,ll n){    ll m = n-1;    int j = 0;    while(!(m&1))    {        j++;        m >>= 1;    }    ll x = pow_mod(a,m,n);    if(x == 1 || x == n-1)        return false;    while(j--)    {        x = x*x%n;        if(x == n-1)            return false;    }    return true;}bool Miller_Rabin(ll n){    if(n < 2)        return false;    if(n == 2)        return true;    if(!(n&1))        return false;    for(int i=1;i<=5;i++)   //5次测试    {        ll a = random(n-2)+1;        if(Witness(a,n))            return false;    }    return true;}int main(){    srand(time(NULL));}