ll e_gcd(ll a,ll b,int &x,int &y){
    if (b==0){
        x=1; y=0; return a;
    }
    ll d=e_gcd(b,a%b,x,y);
    ll t=x; x=y;
    y=t-(a/b)*y;
    return d;
}
void CRT(int n){
    int M=1; ans=0;
    for (int i=1;i<=n;i++) M*=m[i];
    for (int i=1;i<=n;i++){
        int x,y,Mi=M/m[i];
        e_gcd(Mi,m[i],x,y);
        ans=mo(ans+a[i]*Mi*x,M);
    } 
}

ll e_gcd(ll a,ll b,ll &x,ll &y){
    if (b==0){
        x=1; y=0; return a;
    }
    ll d=e_gcd(b,a%b,x,y);
    ll t=x; x=y;
    y=t-(a/b)*y;
    return d;
}
ll e_crt(int n)
{
    ll M=m[1],R=r[1],x,y,d;
    for (int i=2;i<=n;++i)
    {
        d=e_gcd(M,m[i],x,y);
        if ((r[i]-R)%d) return -1;
        x=(r[i]-R)/d*x%(m[i]/d);
        R+=x*M; M=M/d*m[i]; R%=M;
    }
    return R>0?R:R+M;
}