import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.NoSuchElementException;

public class Main{
	
		public static void main(String[] args) {
			new Main().run();
		}
		
		final long mod=998244353;
		
		long pow(long a, long n) {
			if (n==0) return 1;
			return pow(a*a%mod,n/2)*(n%2==1?a:1)%mod;
		}
		
		long inv(long a) {
			return pow(a,mod-2);
		}
		
		long c(long n, int k) {
			long ret=1;
			for (int i=0;i<k;++i) {
				ret=ret*(n-i)%mod;
			}
			for (int i=1;i<=k;++i) {
				ret=ret*inv(i)%mod;
			}
			return ret;
		}
		
		long c2(long n, int k) {
			return c(n+k-1,k);
		}
		
		void run() {
			FastScanner sc=new FastScanner();
			PrintWriter pw = new PrintWriter(System.out);
			int N=sc.nextInt();
			int M=sc.nextInt();
			long ans=M%mod*c2(M+1,2*N)%mod-c2(M,2*N+1);
			ans=ans*inv(2)%mod;
			ans=(ans%mod+mod)%mod;
			System.out.println(ans);
			pw.close();
		}
		
		void tr(Object...objects) {System.out.println(Arrays.deepToString(objects));}	
	}
	
	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() {
	    	return (int)nextLong();
	    }
	}