# Python: Print the number of prime numbers which are less than or equal to a given integer

## Python Basic - 1: Exercise-38 with Solution

Write a Python program to print the number of prime numbers which are less than or equal to a given integer.

**Input:**

n (1 ≤ n ≤ 999,999)

**Sample Solution**:

**Python Code:**

```
primes = [1] * 500000
primes[0] = 0
for i in range(3, 1000, 2):
if primes[i // 2]:
primes[(i * i) // 2::i] = [0] * len(primes[(i * i) // 2::i])
print("Input the number(n):")
n=int(input())
if n < 4:
print("Number of prime numbers which are less than or equal to n.:",n - 1)
else:
print("Number of prime numbers which are less than or equal to n.:",sum(primes[:(n + 1) // 2]) + 1)
```

Sample Output:

Input the number(n): 35 Number of prime numbers which are less than or equal to n.: 11

**Pictorial Presentation:**

**Flowchart:**

**Python Code Editor:**

**Have another way to solve this solution? Contribute your code (and comments) through Disqus.**

**Previous:** Write a Python program which reads an integer n and find the number of combinations of a,b,c and d (0 ≤ a,b,c,d ≤ 9) where (a + b + c + d) will be equal to n.

**Next:** Write a program to compute the radius and the central coordinate (x, y) of a circle which is constructed by three given points on the plane surface.

**What is the difficulty level of this exercise?**

Test your Python skills with w3resource's quiz

## Python: Tips of the Day

**Returns the symmetric difference between two lists, after applying the provided function to each list element of both**

Example:

def tips_symmetric_difference_by(p, q, fn): _p, _q = set(map(fn, p)), set(map(fn, q)) return [item for item in p if fn(item) not in _q] + [item for item in q if fn(item) not in _p] from math import floor print(tips_symmetric_difference_by([4.2, 2.4], [4.6, 6.8],floor))

Output:

[2.4, 6.8]

**New Content published on w3resource :**- Python Numpy exercises
- Python GeoPy Package exercises
- Python Pandas exercises
- Python nltk exercises
- Python BeautifulSoup exercises
- Form Template
- Composer - PHP Package Manager
- PHPUnit - PHP Testing
- Laravel - PHP Framework
- Angular - JavaScript Framework
- React - JavaScript Library
- Vue - JavaScript Framework
- Jest - JavaScript Testing Framework