读入挂（整型）

inline int read()
{
    int x = 0,f = 1;
    char c = getchar();
    while ((c < '0' || c > '9') && c != EOF)
    {
        if (c == '-') f = -1;
        c = getchar();
    }
    while ((c <='9' && c >='0') && c != EOF)
    {
        x = x * 10 + c - '0';
        c = getchar();
    }
    return x * f;
}