View Code of Problem 103

#include<iostream>
#include<cstdio>
#include<string>
#include<cstring>
#include<algorithm>
#include<vector>
#include<cmath>
using namespace std;
int sh(int n)
{
	if (n == 1)
		return 0;
	if (n == 2 || n == 3)
		return 1;
	for (int i = 2;i < (int)sqrt(n) + 1;i++)
	{
		if (n%i == 0)
			return 0;
	}
	return 1;
}

int main()
{
	int a, b;
	while (cin >> a >> b)
	{
		int cnt = 0;
		for (int i = a;i <= b;i++)
		{
			if (sh(i) == 1)
			{
				cnt++;
			}
		}
		cout << cnt<<endl;
	}
	return 0;
}