C :

#include<stdio.h> 
int main()
{
    int i,n,s=0;
    scanf("%d",&n); 
    for(i=1; i<=n ;i+=2)
    {
     s=s+i;
    }
    printf("%d",s);
    return 0;
}

C++ :

#include <iostream>

using namespace std;

int main(){
    int n,i,s=0;
    cin>>n;
    for(i=1;i<=n;i+=2){
        s+=i;
    }
    cout<<s<<endl;
}

Pascal :

var
  i,a,s:longint;
begin
  read(a);
  for i:=1 to a do
    if i mod 2=1
    then s:=s+i;
  write(s);
end.

Java :

import java.util.*;
public class Main{
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int a = sc.nextInt();
		int sum = 0;
		for(int i = 1;i <= a;i+=2){
			sum+=i;
		}
		
		System.out.println(sum);
	}
}

Python :

n=int(input())
s=0
i=1
for i in range (1,n+1,2):
  s=s+i
print(s)