The flag of Berland is such rectangular field n × m that satisfies following conditions:

  * Flag consists of three colors which correspond to letters 'R', 'G' and 'B'. 
  * Flag consists of three equal in width and height stripes, parralel to each other and to sides of the flag. Each stripe has exactly one color. 
  * Each color should be used in exactly one stripe. 



You are given a field n × m, consisting of characters 'R', 'G' and 'B'. Output "YES" (without quotes) if this field corresponds to correct flag of Berland. Otherwise, print "NO" (without quotes).

Input

The first line contains two integer numbers n and m (1 ≤ n, m ≤ 100) — the sizes of the field.

Each of the following n lines consisting of m characters 'R', 'G' and 'B' — the description of the field.

Output

Print "YES" (without quotes) if the given field corresponds to correct flag of Berland . Otherwise, print "NO" (without quotes).

Examples

Input

6 5
RRRRR
RRRRR
BBBBB
BBBBB
GGGGG
GGGGG


Output

YES


Input

4 3
BRG
BRG
BRG
BRG


Output

YES


Input

6 7
RRRGGGG
RRRGGGG
RRRGGGG
RRRBBBB
RRRBBBB
RRRBBBB


Output

NO


Input

4 4
RRRR
RRRR
BBBB
GGGG


Output

NO

Note

The field in the third example doesn't have three parralel stripes.

Rows of the field in the fourth example are parralel to each other and to borders. But they have different heights — 2, 1 and 1.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.OptionalInt;
import java.util.Set;
import java.util.Stack;
import java.util.StringTokenizer;
import java.util.TreeSet;
import java.util.stream.Collectors;

public class Solution implements Runnable
{
    private void solve() throws IOException
    {
    	//max_int > 2 * 10^9
    	
    	int n = nextInt(); 
    	int m = nextInt();
    	Character[][] array = new Character[n][m];
    	for (int i = 0; i < n; i++) {
        	String s = nextToken();
        	for (int j = 0; j < s.length(); j++) {
        		array[i][j] = s.charAt(j);
        	}
    	}
    	
    	
    	boolean isDoN = n % 3 == 0;
    	boolean isDoM = m % 3 == 0;
    	
    	if (!isDoN && !isDoM) {
    		writer.print("NO");
    		return;
    	}
    	
    	boolean hasAns = true;
    	if (isDoN) {
    		int count = n/3;
    		int rCnt = 0, gCnt = 0, bCnt = 0;
    		
    		for (int i = 0; i < n; i++) {
    			char target = array[i][0];
    			if (target == 'R') {
    				rCnt++;
    				if (rCnt > count || (gCnt > 0 && gCnt < count)|| (bCnt != 0 && bCnt < count)) {
    					hasAns = false;
    		    		break;
    				}
    			}
    			else if (target == 'G') {
    				gCnt++;
    				if (gCnt > count || (rCnt > 0 && rCnt < count)|| (bCnt != 0 && bCnt < count)) {
    					hasAns = false;
    		    		break;
    				}
    			}
				else {
					bCnt++;
    				if (bCnt > count || (rCnt > 0 && rCnt < count)|| (gCnt != 0 && gCnt < count)) {
    					hasAns = false;
    		    		break;
    				}
				}
    			
    			for (int j = 0; j < m; j++) {
    				char c = array[i][j];
    				if (c != target) {
    					hasAns = false;
    					break;
    				}
    			}	
    		}
    		
    		if (hasAns) {
        		writer.print("YES");
        		return;
    		}
    	}
    	
    	hasAns = true;
    	if (isDoM) {
    		int count = m/3;
    		int rCnt = 0, gCnt = 0, bCnt = 0;
    		
    		for (int i = 0; i < m; i++) {
    			char target = array[0][i];
    			if (target == 'R') {
    				rCnt++;
    				if (rCnt > count || (gCnt > 0 && gCnt < count)|| (bCnt != 0 && bCnt < count)) {
    					hasAns = false;
    		    		break;
    				}
    			}
    			else if (target == 'G') {
    				gCnt++;
    				if (gCnt > count || (rCnt > 0 && rCnt < count)|| (bCnt != 0 && bCnt < count)) {
    					hasAns = false;
    		    		break;
    				}
    			}
				else {
					bCnt++;
    				if (bCnt > count || (rCnt > 0 && rCnt < count)|| (gCnt != 0 && gCnt < count)) {
    					hasAns = false;
    		    		break;
    				}
				}
    			
    			for (int j = 0; j < n; j++) {
    				char c = array[j][i];
    				if (c != target) {
    					hasAns = false;
    					break;
    				}
    			}	
    		}
    		
    		if (hasAns) {
        		writer.print("YES");
        		return;
    		}
    	}
    	
    	writer.print("NO");
    	
    }
    
    private List<Integer> primeFact(int n) {
	     List<Integer> factors = new ArrayList<Integer>();
	     
	     for (int i = 2; i <= n / i; i++) {
             while (n % i == 0) {
                 factors.add(i);
                 n /= i;
             }
	     }
	     if (n > 1) 
	    	 factors.add(n);
	     
	     return factors.stream().distinct().collect(Collectors.toList());
    }
    
    private List<Integer> findPrimes(int n)
    {
        boolean prime[] = new boolean[n+1];
        for(int i=0;i<n;i++)
            prime[i] = true;
         
        for(int p = 2; p*p <=n; p++)
        {
            if(prime[p] == true)
            {
                for(int i = p*2; i <= n; i += p)
                    prime[i] = false;
            }
        }
        
        List<Integer> list = new ArrayList<Integer>();
        for(int i = 2; i <= n; i++)
        {
            if(prime[i] == true)
            	list.add(i);
        }
        
        return list;
        
    }
    
    private List<Long> fact(long n)
    {
     TreeSet<Long> factors = new TreeSet<Long>();
     
     factors.add(n);
     factors.add(1L);
     
     for(long i = n - 1; i >= Math.sqrt(n); i--)
	      if(n % i == 0)
	      {
	       factors.add(i);
	       factors.add(n / i);
	      }
     
     return factors.stream().collect(Collectors.toList());
    }
    
    private String minFact(long n) {
    	String str = 1 + " " + n;
	     long min = Long.MAX_VALUE;
	     for(long i = n - 1; i >= Math.sqrt(n); i--)
		      if(n % i == 0) {
		    	  long x = i - n/i;
		    	  
		    	  if (x < min) {
		    		  min = x;
		    		  str = n/i + " " + i;
		    	  }
		       
		      }
	     
	     return str;
    }
    
    private long gcd (long a, long b) {
        BigInteger b1 = BigInteger.valueOf(a);
        BigInteger b2 = BigInteger.valueOf(b);
         
        return b1.gcd(b2).longValue();
    }
    
    private long lcm (long a, long b, long gcd) {
    	return a * b / gcd;
    }
        
    private boolean isPowerOfTwo(long x) {
        return (x != 0) && ((x & (x - 1)) == 0);
    }
    
    private int exponentOfTwo(long n) {
    	return (int)( Math.floor(Math.log(n) / Math.log(2)));

    }

    private Long sumDiagLR (Long[][] array) {
        long sum = 0;
        int i = 0, j = 0;

        while (i < array.length && j < array.length) {
            sum += array[i][j];
            i++;
            j++;
        }

        return sum;
    }

    private Long sumDiagRL (Long[][] array) {
       long sum = 0;
       int i = array.length-1, j = 0;

       while (i >=0 && j < array.length) {
           sum += array[i][j];
           i--;
           j++;
       }

       return sum;
   }


    private BigInteger factorial( String n )
    {
        BigInteger k = new BigInteger( n );
        BigInteger ans = BigInteger.ONE;

        while ( k.compareTo( BigInteger.ONE ) > 0 )
        {
            ans = ans.multiply( k );
            k = k.subtract( BigInteger.ONE );
        }

        return ans;
    }

    private long combinations( long n, long r )
    {
        return ( factorial( String.valueOf( n ) ).divide( ( new BigInteger( String.valueOf( r ) ).multiply( factorial( String.valueOf( n - r ) ) ) ) ) ).longValue();
    }


    private String binaryXOR( String s1, String s2 )
    {
        BigInteger a = new BigInteger( s1, 2 );
        BigInteger b = new BigInteger( s2, 2 );

        return a.xor( b ).toString( 2 );

    }


    private static void findDP( Node node )
    {
        for ( Node child : node.children )
        {
            if ( child.value > node.value )
            {
                child.dp = Math.max( child.dp, node.dp + 1 );
                //findDP( child );
            }
        }
    }

    private static class Obj implements Comparable<Obj>
    {
        String name;
        int value;

        public Obj( int value )
        {
            this.value = value;
        }

        public Obj( String name, int value )
        {
            this.name = name;
            this.value = value;
        }

        @Override
        public int compareTo( Obj o )
        {
            return o.value - this.value;
        }
    }


    private static class Edge
    {
        PNode src;
        PNode des;
        long cost;

        public Edge (PNode src, PNode des, long cost) {
            this.src = src;
            this.des = des;
            this.cost = cost;
        }
    }

    private static class PNode
    {
        List<Edge> edges;
        long value;
        boolean isTrue;

        public PNode() {
            this.edges = new ArrayList<>(  );
            this.isTrue = false;
        }

        public PNode(long value ) {
           this.edges = new ArrayList<>(  );
           this.isTrue = false;
            this.value = value;
       }
    }

    private static class Node
    {
        long value;
        long dp;
        List<Node> children;
        Node parent;

        public  Node(){};

        public Node( int value )
        {
            this.value = value;
            dp = 1;
            children = new ArrayList<Node>();
        }
    }

    private static boolean isInt( String s )
    {
        if ( s.length() < 1 )
            return false;
        else
        {
            for ( char c : s.toCharArray() )
            {
                if ( c < '0' || c > '9' )
                {
                    return false;
                }
            }
        }

        return true;
    }

    private static Map<String, Integer> findSubString( String s, int k )
    {
        Map<String, Integer> map = new HashMap<>();
        for ( int i = 0; i < s.length() - ( k - 1 ); i++ )
        {
            String str = new String( s.substring( i, i + k ) );
            if ( map.containsKey( str ) )
            {
                map.put( str, map.get( str ) + 1 );
            }
            else
            {
                map.put( str, 1 );

            }
        }

        return map;
    }


    //mergesort

    public static Comparable[] mergeSort( Comparable[] list )
    {
        if ( list.length <= 1 )
        {
            return list;
        }

        Comparable[] left = new Comparable[ list.length / 2 ];
        Comparable[] right = new Comparable[ list.length - left.length ];
        System.arraycopy( list, 0, left, 0, left.length );
        System.arraycopy( list, left.length, right, 0, right.length );

        mergeSort( left );
        mergeSort( right );

        merge( left, right, list );
        return list;
    }

    private static void merge( Comparable[] left, Comparable[] right, Comparable[] result )
    {
        int leftIdx = 0;
        int rightIdx = 0;
        int index = 0;

        while ( leftIdx < left.length && rightIdx < right.length )
        {
            if ( left[ leftIdx ].compareTo( right[ rightIdx ] ) < 0 )
            {
                result[ index++ ] = left[ leftIdx ];
                leftIdx++;
            }
            else
            {
                result[ index++ ] = right[ rightIdx ];
                rightIdx++;
            }
        }

        System.arraycopy( left, leftIdx, result, index, left.length - leftIdx );
        System.arraycopy( right, rightIdx, result, index, right.length - rightIdx );
    }

    public static List<Obj> mergeSort( List<Obj> list )
    {
        if ( list.size() <= 1 )
        {
            return list;
        }

        List<Obj> left = new ArrayList( list.subList( 0, list.size() / 2 ) );
        List<Obj> right = new ArrayList( list.subList( left.size(), list.size() ) );

        left = mergeSort( left );
        right = mergeSort( right );

        list = merge( left, right );

        return list;
    }

    private static List<Obj> merge( List<Obj> left, List<Obj> right )
    {
        int leftCounter = 0, rightCounter = 0;
        List<Obj> result = new ArrayList<>();

        while ( leftCounter < left.size() && rightCounter < right.size() )
        {
            Obj leftItem = left.get( leftCounter );
            Obj rightItem = right.get( rightCounter );

            if ( leftItem.compareTo( rightItem ) < 0 )
            {
                result.add( leftItem );
                leftCounter++;
            }
            else
            {
                result.add( rightItem );
                rightCounter++;
            }
        }

        if ( leftCounter >= left.size() )
            result.addAll( right.subList( rightCounter, right.size() ) );
        else if ( rightCounter >= right.size() )
            result.addAll( left.subList( leftCounter, left.size() ) );

        return result;
    }

    public static void main( String[] args )
    {
        new Solution().run();
    }

    BufferedReader reader;
    StringTokenizer tokenizer;
    PrintWriter writer;

    public void run()
    {
        try
        {
            reader = new BufferedReader( new InputStreamReader( System.in ) );
            tokenizer = null;
            writer = new PrintWriter( System.out );
            solve();
            reader.close();
            writer.close();
        }
        catch ( Exception e )
        {
            e.printStackTrace();
            System.exit( 1 );
        }
    }

    int nextInt() throws IOException
    {
        return Integer.parseInt( nextToken() );
    }

    long nextLong() throws IOException
    {
        return Long.parseLong( nextToken() );
    }

    double nextDouble() throws IOException
    {
        return Double.parseDouble( nextToken() );
    }

    String nextToken() throws IOException
    {
        while ( tokenizer == null || !tokenizer.hasMoreTokens() )
        {
            tokenizer = new StringTokenizer( reader.readLine() );
        }
        return tokenizer.nextToken();
    }
    
    public class Tuple {
    	Object fst;
    	Object snd;
    	
    	public Tuple(Object fst, Object snd) {
    		this.fst = fst;
    		this.snd = snd;
    	}
    	
    	public Object getFst() {
    		return fst;
    	}
    	
    	public Object getSnd() {
    		return snd;
    	}
    	
    }

    // Arrays.sort(array, Comparator.comparing((int[] arr) -> arr[1]));
}