输入输出挂（一般用于大量输入输出···········）
//输入正负整数void in(int &m){char ch;int flag = 0;while((ch = getchar()) < '0'|| ch > '9' ){if(ch == '-')flag = 1;for(m = 0; ch >= '0'&& ch <= '9';ch = getchar())m = m*10 + ch - '0';if(flag)m *= -1;}}
template <class T>//适用于正整数inline void scan_d(T & ret){char c;ret = 0;while((c = getchar()) < '0'||c >'9');while(c >= '0'&&c <= '9'){ret = ret*10 + (c - '0'),c = getchar();}}
