输入挂

int Scan()  
{  
    int res = 0, ch, flag = 0;  
    if((ch = getchar()) == '-')  
        flag = 1;  
    else if(ch >= '0' && ch <= '9')  
        res = ch - '0';  
    while((ch = getchar()) >= '0' && ch <= '9' )  
        res = res * 10 + ch - '0';  
    return flag ? -res : res;  
}  
  
ll Scan_l()  
{  
    ll res = 0;  
    int ch, flag = 0;  
    if((ch = getchar()) == '-')  
        flag = 1;  
    else if(ch >= '0' && ch <= '9')  
        res = ch - '0';  
    while((ch = getchar()) >= '0' && ch <= '9' )  
        res = res * 10 + ch - '0';  
    return flag ? -res : res;  
}