#include<stdio.h>
int main()
{
	int num, i, tag = 0;
	printf("输入一个数\n");
	scanf("%d", &num);
	for (i = 2; i <= num-1; i++)
	{
		if (num%i == 0)
			tag = 1;
	}
	if (tag == 1)
		printf("No\n");
	else
		printf("Yes\n");
	return 0;
}