read()

inline int read()
{
    int res=0,f=1;
    char ch=getchar();
    while (!isdigit(ch))
    {
        if (ch=='-')
        {
            f=-f;
        }
        ch=getchar();
    }
    while (isdigit(ch))
    {
        res=(res<<3)+(res<<1)+ch-'0';
        ch=getchar();
    }
    return f*res;
}