/*
ID: anonymo14
TASK: wormhole
LANG: C++                 
*/
#include<bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<pair<int,int>> vpii;

#define F first
#define S second
#define PU push
#define PUF push_front
#define PUB push_back
#define PO pop
#define POF pop_front
#define POB pop_back

#define REP(i,a,b) for(int i=a; i<=b; i++)

#define MOD 1000000007

void solve(int test_case) {
	string s;
	cin>>s;
	if(s=="SUN")cout<<7;
	else if(s=="MON")cout<<6;
	else if(s=="TUE")cout<<5;
	else if(s=="WED")cout<<4;
	else if(s=="THU")cout<<3;
	else if(s=="FRI")cout<<2;
	else if(s=="SAT")cout<<1;
	
}

int main() {
	
	////// FILE BASED IO////
	//freopen("wormhole.in", "r", stdin);
	//freopen("wormhole.out", "w", stdout);
	///////////////
	
	ios::sync_with_stdio(0);
	cin.tie(0);
	int t=1;
	//cin>>t;
	REP(i,1,t) {
		solve(i);
	}
	return 0;
}	


#include<bits/stdc++.h>


using namespace std;

typedef long long ll;

#define pi 2*acos(0.0)


int main(void)
{
    //ios_base::sync_with_stdio(false);
    //cin.tie(0);
    // cout.tie(0);
  set<ll>s;

  int n;
  cin>>n;
  bool flag = true;
  while(n--)
  {
      ll x;
      cin>>x;
      if(s.count(x)>0)
      {
          flag = false;
      }
      s.insert(x);
  }
  if(flag)
  {
      cout<<"YES"<<endl;
  }
  else
  {
      cout<<"NO"<<endl;
  }
}
