[板子]快读

int rd(){
	int x=0,p=1;
	char ch=getchar();
	while(ch>'9' || ch<'0'){
		if(ch=='-'){
			p=-1;
		}
		ch=getchar();
	}
	while(ch>='0' && ch<='9'){
		x=x*10+ch-'0';
		ch=getchar();
	}
	return x*p;
}