import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; import java.util.*; public class Main { static final int INF = 2 << 28; static final long INF_L = 2L << 60; static final int MOD = 1000000007; static final long MOD_L = 1000000007L; static final int[] vx_4 = {1,0,-1,0}; static final int[] vy_4 = {0,1,0,-1}; static final int[] vx_5 = {1,0,-1,0,0}; static final int[] vy_5 = {0,1,0,-1,0}; static final int[] vx_8 = {1,1,1,0,0,-1,-1,-1}; static final int[] vy_8 = {1,0,-1,1,-1,1,0,-1}; static final int[] vx_9 = {1,1,1,0,0,0,-1,-1,-1}; static final int[] vy_9 = {1,0,-1,1,0,-1,1,0,-1}; public static void main(String[] args) { FastScanner sc = new FastScanner(); PrintWriter out = new PrintWriter(System.out); int N = sc.nextInt(); int[] count = new int[12]; int kk = 0; HashMap map = new HashMap(); for(int i = 0; i < N; i++) { String in = sc.next(); if(map.containsKey(in)) { count[map.get(in)]++; } else { map.put(in, kk); count[kk++]++; } } boolean ok = true; int pre = -1; while(N != 0) { boolean gg = false; for(int i = 0; i < count.length; i++) { if(count[i] == 0 || i == pre) continue; count[i]--; N--; pre = i; gg = true; break; } if(!gg) { ok = false; break; } } if(ok)System.out.println("YES"); else System.out.println("NO"); } } class FastScanner { private final InputStream in = System.in; private final byte[] buffer = new byte[1024]; private int ptr = 0; private int buflen = 0; private boolean hasNextByte() { if (ptr < buflen) { return true; }else{ ptr = 0; try { buflen = in.read(buffer); } catch (IOException e) { e.printStackTrace(); } if (buflen <= 0) { return false; } } return true; } private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;} private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;} private void skipUnprintable() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++;} public boolean hasNext() { skipUnprintable(); return hasNextByte();} public String next() { if (!hasNext()) throw new NoSuchElementException(); StringBuilder sb = new StringBuilder(); int b = readByte(); while(isPrintableChar(b)) { sb.appendCodePoint(b); b = readByte(); } return sb.toString(); } public long nextLong() { if (!hasNext()) throw new NoSuchElementException(); long n = 0; boolean minus = false; int b = readByte(); if (b == '-') { minus = true; b = readByte(); } if (b < '0' || '9' < b) { throw new NumberFormatException(); } while(true){ if ('0' <= b && b <= '9') { n *= 10; n += b - '0'; }else if(b == -1 || !isPrintableChar(b)){ return minus ? -n : n; }else{ throw new NumberFormatException(); } b = readByte(); } } public int nextInt() { if (!hasNext()) throw new NoSuchElementException(); int n = 0; boolean minus = false; int b = readByte(); if (b == '-') { minus = true; b = readByte(); } if (b < '0' || '9' < b) { throw new NumberFormatException(); } while(true){ if ('0' <= b && b <= '9') { n *= 10; n += b - '0'; }else if(b == -1 || !isPrintableChar(b)){ return minus ? -n : n; }else{ throw new NumberFormatException(); } b = readByte(); } } }