C :

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>

int main()
{
    //freopen("in","r",stdin);
  //  freopen("out","w",stdout);

    int n ;
    int count,i;
    while(scanf("%d",&n)!=EOF)
    {
        count =0;
        for(i=1;i<=n;i++)
        {
            if((i % 7 == 0 || i % 11 ==0) )
            {
                if(i%7 == 0 && i % 11==0)
                    continue;
                else
                    count++;
            }
        }
        printf("%d\n",count);
    }


	return 0;

}

C++ :

#include<iostream>
using namespace std;
int main()
{
	int i;
	int n;
	while(cin>>n)
	{
		int sum=0;
		for(i=1;i<=n;i++)
		{
			if(i%7==0 || i%11==0 )
			{
				if(i%7==0 && i%11==0);
				else sum++;
			}
		}
		cout<<sum<<endl;
	}
	return 0;
}