#include <bits/stdc++.h>
using namespace std;
#define all(c) (c).begin(),(c).end()
#define rrep(i,n) for(int i=(int)(n)-1;i>=0;i--)
#define REP(i,m,n) for(int i=(int)(m);i<(int)(n);i++)
#define rep(i,n) REP(i,0,n)
#define iter(c) __typeof((c).begin())
#define tr(it,c) for(iter(c) it=(c).begin();it!=(c).end();it++)
#define pb(a) push_back(a)
#define rd(a) cin>>(a)
#define RD(a,b) cin>>(a)>>(b)
#define pr(a) cout<<(a)<<endl
#define PR(a,b) cout<<(a)<<" "<<(b)<<endl
#define F first
#define S second
#define ll long long
bool check(int n,int m,int x,int y){return (x<0||x>=n||y<0||y>=m)?false:true;}
const ll MAX=1000000007,MAXL=1LL<<60,dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};
typedef pair<int,int> P;

ll days(ll y, ll m, ll d){
    if(m < 3) y--, m += 12;
    return 365 * y + y / 4 - y / 100 + y / 400 + (153 * m + 8) / 5 + d;
}

int main() {
  ll n;
  cin >> n;
  ll cnt=0;
  ll d=days(2014,7,23)%7;
  REP(i,2015,n+1) {
    if(days(i,7,23)%7==d) {
      cnt++;
      i+=4;
    }
  }
  pr(cnt);
  return 0;
}