View Code of Problem 103

#include <stdio.h>

#define N 1000

int main()
{
	int a, b, i, j, k, count = 0, num[N] = {1, 1};
	scanf("%d%d", &a, &b);
	for(i = 2; i <= b; i++)
	{
		if(num[i] == 0)
		{
			for(j = 2 * i; j <= b; j += i)
			{
				num[j] = 1;
			}
		}
	}
	for(i = a; i <= b; i++)
	{
		if(num[i] == 0)
		{
			count++;
		}
	}
	printf("%d\n", count);
	return 0;
}