快读

inline int read(){//我喜欢快读
    int num = 0;
    char c;
    bool flag = false;
    while ((c = getchar()) == ' ' || c == '\n' || c == '\r');
        if (c == '-') flag = true;
    else
        num = c - '0';
    while (isdigit(c = getchar()))
    num = num * 10 + c - '0';
    return (flag ? -1 : 1) * num;
}