#include "bits/stdc++.h" using namespace std; typedef long long ll; typedef long double ld; #define mp make_pair #define pb push_back #define FOR(i,a,x) for(int i=(a);i<(x);i++) #define rep(i,n) FOR(i,0,n) #define xFOR(i,a,x) for(int i=(a);i<=(x);i++) #define sor(v) sort(v.begin(),v.end()) #define rev(s) reverse(s.begin(),s.end()) #define lb(vec,a) lower_bound(vec.begin(),vec.end()) #define ub(vec,a) upper_bound(vec.begin(),vec.end()) #define uniq(vec) vec.erace(unique(vec.begin(),vec.end(),vec.end)) #define mp1(a,b,c) P1(a,P(b,c)) #define all(x) (x).begin(),(x).end() #define debug(X) cout<<"["<<#X<<"]"<= 0 && y >= 0 && xMax > x && yMax > y; } inline int toInt(string s) { int v; istringstream sin(s); sin >> v; return v; } template inline string toString(const T &a) { ostringstream oss; oss << a; return oss.str(); } template inline T sqr(T x) { return x*x; } const int dx[8] = { 1, 0, -1, 0, 1, 1, -1, -1 }, dy[8] = { 0, -1, 0, 1, -1, 1, -1, 1 }; //const int mod = 1000000007; const int INF = 1e9; const int NIL = -1; #define MAX_N 10010 #define MAX_K 100 #define MAX_V 10000 string s; string ans1,ans2; int main() { int n; cin >> n; cin >> s; if (s.size() == 1)cout << "NO"<= 4)cout << "YES" << endl; return 0; }