数据读入加速

//适用于正整数

template <class T>
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();
}

//适用于正负整数

template <class T>
inline bool scan_d(T &ret) {
   char c; int sgn;
   if(c=getchar(),c==EOF) return 0; //EOF
   while(c!='-'&&(c<'0'||c>'9')) c=getchar();
   sgn=(c=='-')?-1:1;
   ret=(c=='-')?0:(c-'0');
   while(c=getchar(),c>='0'&&c<='9') ret=ret*10+(c-'0');
   ret*=sgn;
   return 1;
}

//适用于正负数,(int,long long,float,double)

template <class T>
bool scan_d(T &ret){
	char c; int sgn; T bit=0.1;
	if(c=getchar(),c==EOF) return 0;
	while(c!='-'&&c!='.'&&(c<'0'||c>'9')) c=getchar();
	sgn=(c=='-')?-1:1;
	ret=(c=='-')?0:(c-'0');
	while(c=getchar(),c>='0'&&c<='9') ret=ret*10+(c-'0');
	if(c==' '||c=='\n'){ ret*=sgn; return 1; }
	while(c=getchar(),c>='0'&&c<='9') ret+=(c-'0')*bit,bit/=10;
	ret*=sgn;
	return 1;
}

//输出（不常用）

inline void out(int x) {
   if(x>9) out(x/10);
   putchar(x%10+'0');
}