C#简单问题求高人指点

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace zy4._3
{
public abstract class A
{
private int m_y;
public virtual int x
{
get { return 0; }
}
public virtual int Y
{
get { return m_y; }
set { m_y = value; }
}
public abstract int Z { get;set;}
}
public class B : A
{
private int m_z;
public override int X
{
get { return base.x + 1; }
}
public override int Y
{
set { base.m_y = value; }
}
public override int z
{
get { return m_z; }
}
}
}

少个括号！！！

多了一个括号，public class B:A上面那个

public class B:A 前面加上“}”