快读

inline long long read()
{    long long x=0ll; long long f=1ll; 
	char ch=getchar();    
	for(;!isdigit(ch);ch=getchar()) {if(ch=='-') f = -1;}    
	for(; isdigit(ch);ch=getchar()) {x = x*10ll+ch-'0';}    
	return x*f;
}