#include <bits/stdc++.h>
#define rep(i,l,r) for(int i=l;i<=r;i++)
#define per(i,r,l) for(int i=r;i>=l;i--)
#define IMAX 0x3f3f3f3f
#define LLMAX 0x3f3f3f3f3f3f3f3f
using namespace std;
typedef long long ll;
typedef double db;
inline int read() {
  int x=0,f=1;
  char c=getchar();
  while(!isdigit(c)){if(c=='-')f=-1;c=getchar();}
  while(isdigit(c)){x=x*10+c-'0';c=getchar();}
  return x*f;
}
int n;
ll sum;
signed main() {
  n=read();
  rep(i,1,n){
    if(i%3!=0&&i%5!=0){
      sum+=i;
    }
  }
  printf("%lld\n",sum);
  return 0;
}