处理大数输入的模板

inline int Read()
{
    int x = 0, f = 1, c = getchar();
    for (; !isdigit(c); c = getchar())
        if (c == '-')
            f = -1;
    for (;  isdigit(c); c = getchar())
        x = x * 10 + c - '0';
    return x * f;
}