咋TLE了？

#include <bits/stdc++.h>
#include <iostream>
#include <stdio.h>

using namespace std;

int is_prime ( int n )
{
	if ( n == 0 || n == 1 )
	{
		return 0;
	}
//	int m;
//	m = sqrt ( s );
	for ( int i = 2; i < n; i ++ )
	{
		if ( n % i == 0 )
		{
			return 0;
		}
	}
	return 1;
}

int main ()
{
	ios::sync_with_stdio ( 0 );
	cin.tie ( 0 ), cout.tie ( 0 );
	int l, r, sum = 0;
	cin >> l >> r;
	if ( l > r )
	{
		cout << 0 << endl;
		return 0;
	}
	for ( int i = l; i <= r; i ++ )
	{
		if ( is_prime ( i ) == 0 )
		{
			continue;
		}
		else
		{
			sum ++;
		}
	}
	cout << sum;
	return 0;
}