

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;



public class Main {
	
	public static void main(String[] args) throws java.lang.Exception {
			MyScanner sc = new MyScanner();
	      out = new PrintWriter(new BufferedOutputStream(System.out));
	      
	      String input[] = sc.nextLine().split(" ");
	      int n = Integer.parseInt(input[0]);
	      int m = Integer.parseInt(input[1]);
	      int even[] = new int[n];
	      int odd[] = new int[m];
	      int p = 0;
	      for(int i = 1; i <= n; i++)
	    	  even[p++] = 2 * i;
	      p = 0;
	      for(int i = 1; i <= m; i++)
	    	  odd[p++] = (2 * i) - 1;
	      int count = 0;
	      for(int i = 0; i < n; i++) {
	    	  for(int j = i + 1; j < n; j++)
	    		  count++;
	      }
	      
	      for(int i = 0; i < m; i++) {
	    	  for(int j = i + 1; j < m; j++)
	    		  count++;
	      }
	      System.out.println(count);
	      out.close();
	}
	public static PrintWriter out;

	   public static class MyScanner {
	      BufferedReader br;
	      StringTokenizer st;
	 
	      public MyScanner() {
	         br = new BufferedReader(new InputStreamReader(System.in));
	      }
	 
	      String next() {
	          while (st == null || !st.hasMoreElements()) {
	              try {
	                  st = new StringTokenizer(br.readLine());
	              } catch (IOException e) {
	                  e.printStackTrace();
	              }
	          }
	          return st.nextToken();
	      }
	 
	      int nextInt() {
	          return Integer.parseInt(next());
	      }
	 
	      long nextLong() {
	          return Long.parseLong(next());
	      }
	 
	      double nextDouble() {
	          return Double.parseDouble(next());
	      }
	 
	      String nextLine(){
	          String str = "";
		  try {
		     str = br.readLine();
		  } catch (IOException e) {
		     e.printStackTrace();
		  }
		  return str;
	      }

	   }

} import java.io.BufferedOutputStream; BufferedOutputStream java.io import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.PrintWriter; PrintWriter java.io import java.util.StringTokenizer; StringTokenizer java.util public class Main {
	
	public static void main(String[] args) throws java.lang.Exception {
			MyScanner sc = new MyScanner();
	      out = new PrintWriter(new BufferedOutputStream(System.out));
	      
	      String input[] = sc.nextLine().split(" ");
	      int n = Integer.parseInt(input[0]);
	      int m = Integer.parseInt(input[1]);
	      int even[] = new int[n];
	      int odd[] = new int[m];
	      int p = 0;
	      for(int i = 1; i <= n; i++)
	    	  even[p++] = 2 * i;
	      p = 0;
	      for(int i = 1; i <= m; i++)
	    	  odd[p++] = (2 * i) - 1;
	      int count = 0;
	      for(int i = 0; i < n; i++) {
	    	  for(int j = i + 1; j < n; j++)
	    		  count++;
	      }
	      
	      for(int i = 0; i < m; i++) {
	    	  for(int j = i + 1; j < m; j++)
	    		  count++;
	      }
	      System.out.println(count);
	      out.close();
	}
	public static PrintWriter out;

	   public static class MyScanner {
	      BufferedReader br;
	      StringTokenizer st;
	 
	      public MyScanner() {
	         br = new BufferedReader(new InputStreamReader(System.in));
	      }
	 
	      String next() {
	          while (st == null || !st.hasMoreElements()) {
	              try {
	                  st = new StringTokenizer(br.readLine());
	              } catch (IOException e) {
	                  e.printStackTrace();
	              }
	          }
	          return st.nextToken();
	      }
	 
	      int nextInt() {
	          return Integer.parseInt(next());
	      }
	 
	      long nextLong() {
	          return Long.parseLong(next());
	      }
	 
	      double nextDouble() {
	          return Double.parseDouble(next());
	      }
	 
	      String nextLine(){
	          String str = "";
		  try {
		     str = br.readLine();
		  } catch (IOException e) {
		     e.printStackTrace();
		  }
		  return str;
	      }

	   }

} Main public static PrintWriter out; out public static void main(String[] args) throws java.lang.Exception {
			MyScanner sc = new MyScanner();
	      out = new PrintWriter(new BufferedOutputStream(System.out));
	      
	      String input[] = sc.nextLine().split(" ");
	      int n = Integer.parseInt(input[0]);
	      int m = Integer.parseInt(input[1]);
	      int even[] = new int[n];
	      int odd[] = new int[m];
	      int p = 0;
	      for(int i = 1; i <= n; i++)
	    	  even[p++] = 2 * i;
	      p = 0;
	      for(int i = 1; i <= m; i++)
	    	  odd[p++] = (2 * i) - 1;
	      int count = 0;
	      for(int i = 0; i < n; i++) {
	    	  for(int j = i + 1; j < n; j++)
	    		  count++;
	      }
	      
	      for(int i = 0; i < m; i++) {
	    	  for(int j = i + 1; j < m; j++)
	    		  count++;
	      }
	      System.out.println(count);
	      out.close();
	} main {
			MyScanner sc = new MyScanner();
	      out = new PrintWriter(new BufferedOutputStream(System.out));
	      
	      String input[] = sc.nextLine().split(" ");
	      int n = Integer.parseInt(input[0]);
	      int m = Integer.parseInt(input[1]);
	      int even[] = new int[n];
	      int odd[] = new int[m];
	      int p = 0;
	      for(int i = 1; i <= n; i++)
	    	  even[p++] = 2 * i;
	      p = 0;
	      for(int i = 1; i <= m; i++)
	    	  odd[p++] = (2 * i) - 1;
	      int count = 0;
	      for(int i = 0; i < n; i++) {
	    	  for(int j = i + 1; j < n; j++)
	    		  count++;
	      }
	      
	      for(int i = 0; i < m; i++) {
	    	  for(int j = i + 1; j < m; j++)
	    		  count++;
	      }
	      System.out.println(count);
	      out.close();
	} MyScanner sc = new MyScanner(); sc new MyScanner() out = new PrintWriter(new BufferedOutputStream(System.out)) out new PrintWriter(new BufferedOutputStream(System.out)) String input[] = sc.nextLine().split(" "); input sc.nextLine().split(" ") sc.nextLine().split sc.nextLine() sc.nextLine sc " " int n = Integer.parseInt(input[0]); n Integer.parseInt(input[0]) Integer.parseInt Integer input[0] input 0 int m = Integer.parseInt(input[1]); m Integer.parseInt(input[1]) Integer.parseInt Integer input[1] input 1 int even[] = new int[n]; even new int[n] n int odd[] = new int[m]; odd new int[m] m int p = 0; p 0 for(int i = 1; i <= n; i++)
	    	  even[p++] = 2 * i; int i = 1; int i = 1; i 1 i <= n i n i++ i++ i even[p++] = 2 * i; even[p++] = 2 * i even[p++] even p++ p 2 * i 2 i p = 0 p 0 for(int i = 1; i <= m; i++)
	    	  odd[p++] = (2 * i) - 1; int i = 1; int i = 1; i 1 i <= m i m i++ i++ i odd[p++] = (2 * i) - 1; odd[p++] = (2 * i) - 1 odd[p++] odd p++ p (2 * i) - 1 (2 * i) 2 i 1 int count = 0; count 0 for(int i = 0; i < n; i++) {
	    	  for(int j = i + 1; j < n; j++)
	    		  count++;
	      } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
	    	  for(int j = i + 1; j < n; j++)
	    		  count++;
	      } {
	    	  for(int j = i + 1; j < n; j++)
	    		  count++;
	      } for(int j = i + 1; j < n; j++)
	    		  count++; int j = i + 1; int j = i + 1; j i + 1 i 1 j < n j n j++ j++ j count++; count++ count for(int i = 0; i < m; i++) {
	    	  for(int j = i + 1; j < m; j++)
	    		  count++;
	      } int i = 0; int i = 0; i 0 i < m i m i++ i++ i {
	    	  for(int j = i + 1; j < m; j++)
	    		  count++;
	      } {
	    	  for(int j = i + 1; j < m; j++)
	    		  count++;
	      } for(int j = i + 1; j < m; j++)
	    		  count++; int j = i + 1; int j = i + 1; j i + 1 i 1 j < m j m j++ j++ j count++; count++ count System.out.println(count) System.out.println System.out System System.out count out.close() out.close out String[] args args public static class MyScanner {
	      BufferedReader br;
	      StringTokenizer st;
	 
	      public MyScanner() {
	         br = new BufferedReader(new InputStreamReader(System.in));
	      }
	 
	      String next() {
	          while (st == null || !st.hasMoreElements()) {
	              try {
	                  st = new StringTokenizer(br.readLine());
	              } catch (IOException e) {
	                  e.printStackTrace();
	              }
	          }
	          return st.nextToken();
	      }
	 
	      int nextInt() {
	          return Integer.parseInt(next());
	      }
	 
	      long nextLong() {
	          return Long.parseLong(next());
	      }
	 
	      double nextDouble() {
	          return Double.parseDouble(next());
	      }
	 
	      String nextLine(){
	          String str = "";
		  try {
		     str = br.readLine();
		  } catch (IOException e) {
		     e.printStackTrace();
		  }
		  return str;
	      }

	   } MyScanner BufferedReader br; br StringTokenizer st; st public MyScanner() {
	         br = new BufferedReader(new InputStreamReader(System.in));
	      } MyScanner {
	         br = new BufferedReader(new InputStreamReader(System.in));
	      } br = new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) String next() {
	          while (st == null || !st.hasMoreElements()) {
	              try {
	                  st = new StringTokenizer(br.readLine());
	              } catch (IOException e) {
	                  e.printStackTrace();
	              }
	          }
	          return st.nextToken();
	      } next {
	          while (st == null || !st.hasMoreElements()) {
	              try {
	                  st = new StringTokenizer(br.readLine());
	              } catch (IOException e) {
	                  e.printStackTrace();
	              }
	          }
	          return st.nextToken();
	      } while (st == null || !st.hasMoreElements()) {
	              try {
	                  st = new StringTokenizer(br.readLine());
	              } catch (IOException e) {
	                  e.printStackTrace();
	              }
	          } st == null || !st.hasMoreElements() st == null st null !st.hasMoreElements() st.hasMoreElements() st.hasMoreElements st {
	              try {
	                  st = new StringTokenizer(br.readLine());
	              } catch (IOException e) {
	                  e.printStackTrace();
	              }
	          } try {
	                  st = new StringTokenizer(br.readLine());
	              } catch (IOException e) {
	                  e.printStackTrace();
	              } catch (IOException e) {
	                  e.printStackTrace();
	              } IOException e {
	                  e.printStackTrace();
	              } e.printStackTrace() e.printStackTrace e {
	                  st = new StringTokenizer(br.readLine());
	              } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt() {
	          return Integer.parseInt(next());
	      } nextInt {
	          return Integer.parseInt(next());
	      } return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next long nextLong() {
	          return Long.parseLong(next());
	      } nextLong {
	          return Long.parseLong(next());
	      } return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next double nextDouble() {
	          return Double.parseDouble(next());
	      } nextDouble {
	          return Double.parseDouble(next());
	      } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next String nextLine(){
	          String str = "";
		  try {
		     str = br.readLine();
		  } catch (IOException e) {
		     e.printStackTrace();
		  }
		  return str;
	      } nextLine {
	          String str = "";
		  try {
		     str = br.readLine();
		  } catch (IOException e) {
		     e.printStackTrace();
		  }
		  return str;
	      } String str = ""; str "" try {
		     str = br.readLine();
		  } catch (IOException e) {
		     e.printStackTrace();
		  } catch (IOException e) {
		     e.printStackTrace();
		  } IOException e {
		     e.printStackTrace();
		  } e.printStackTrace() e.printStackTrace e {
		     str = br.readLine();
		  } str = br.readLine() str br.readLine() br.readLine br return str; str public class Main {
	
	public static void main(String[] args) throws java.lang.Exception {
			MyScanner sc = new MyScanner();
	      out = new PrintWriter(new BufferedOutputStream(System.out));
	      
	      String input[] = sc.nextLine().split(" ");
	      int n = Integer.parseInt(input[0]);
	      int m = Integer.parseInt(input[1]);
	      int even[] = new int[n];
	      int odd[] = new int[m];
	      int p = 0;
	      for(int i = 1; i <= n; i++)
	    	  even[p++] = 2 * i;
	      p = 0;
	      for(int i = 1; i <= m; i++)
	    	  odd[p++] = (2 * i) - 1;
	      int count = 0;
	      for(int i = 0; i < n; i++) {
	    	  for(int j = i + 1; j < n; j++)
	    		  count++;
	      }
	      
	      for(int i = 0; i < m; i++) {
	    	  for(int j = i + 1; j < m; j++)
	    		  count++;
	      }
	      System.out.println(count);
	      out.close();
	}
	public static PrintWriter out;

	   public static class MyScanner {
	      BufferedReader br;
	      StringTokenizer st;
	 
	      public MyScanner() {
	         br = new BufferedReader(new InputStreamReader(System.in));
	      }
	 
	      String next() {
	          while (st == null || !st.hasMoreElements()) {
	              try {
	                  st = new StringTokenizer(br.readLine());
	              } catch (IOException e) {
	                  e.printStackTrace();
	              }
	          }
	          return st.nextToken();
	      }
	 
	      int nextInt() {
	          return Integer.parseInt(next());
	      }
	 
	      long nextLong() {
	          return Long.parseLong(next());
	      }
	 
	      double nextDouble() {
	          return Double.parseDouble(next());
	      }
	 
	      String nextLine(){
	          String str = "";
		  try {
		     str = br.readLine();
		  } catch (IOException e) {
		     e.printStackTrace();
		  }
		  return str;
	      }

	   }

} public class Main {
	
	public static void main(String[] args) throws java.lang.Exception {
			MyScanner sc = new MyScanner();
	      out = new PrintWriter(new BufferedOutputStream(System.out));
	      
	      String input[] = sc.nextLine().split(" ");
	      int n = Integer.parseInt(input[0]);
	      int m = Integer.parseInt(input[1]);
	      int even[] = new int[n];
	      int odd[] = new int[m];
	      int p = 0;
	      for(int i = 1; i <= n; i++)
	    	  even[p++] = 2 * i;
	      p = 0;
	      for(int i = 1; i <= m; i++)
	    	  odd[p++] = (2 * i) - 1;
	      int count = 0;
	      for(int i = 0; i < n; i++) {
	    	  for(int j = i + 1; j < n; j++)
	    		  count++;
	      }
	      
	      for(int i = 0; i < m; i++) {
	    	  for(int j = i + 1; j < m; j++)
	    		  count++;
	      }
	      System.out.println(count);
	      out.close();
	}
	public static PrintWriter out;

	   public static class MyScanner {
	      BufferedReader br;
	      StringTokenizer st;
	 
	      public MyScanner() {
	         br = new BufferedReader(new InputStreamReader(System.in));
	      }
	 
	      String next() {
	          while (st == null || !st.hasMoreElements()) {
	              try {
	                  st = new StringTokenizer(br.readLine());
	              } catch (IOException e) {
	                  e.printStackTrace();
	              }
	          }
	          return st.nextToken();
	      }
	 
	      int nextInt() {
	          return Integer.parseInt(next());
	      }
	 
	      long nextLong() {
	          return Long.parseLong(next());
	      }
	 
	      double nextDouble() {
	          return Double.parseDouble(next());
	      }
	 
	      String nextLine(){
	          String str = "";
		  try {
		     str = br.readLine();
		  } catch (IOException e) {
		     e.printStackTrace();
		  }
		  return str;
	      }

	   }

} Main


import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;



public class Main {
	
	public static void main(String[] args) throws java.lang.Exception {
			MyScanner sc = new MyScanner();
	      out = new PrintWriter(new BufferedOutputStream(System.out));
	      
	      String input[] = sc.nextLine().split(" ");
	      int n = Integer.parseInt(input[0]);
	      int m = Integer.parseInt(input[1]);
	      int even[] = new int[n];
	      int odd[] = new int[m];
	      int p = 0;
	      for(int i = 1; i <= n; i++)
	    	  even[p++] = 2 * i;
	      p = 0;
	      for(int i = 1; i <= m; i++)
	    	  odd[p++] = (2 * i) - 1;
	      int count = 0;
	      for(int i = 0; i < n; i++) {
	    	  for(int j = i + 1; j < n; j++)
	    		  count++;
	      }
	      
	      for(int i = 0; i < m; i++) {
	    	  for(int j = i + 1; j < m; j++)
	    		  count++;
	      }
	      System.out.println(count);
	      out.close();
	}
	public static PrintWriter out;

	   public static class MyScanner {
	      BufferedReader br;
	      StringTokenizer st;
	 
	      public MyScanner() {
	         br = new BufferedReader(new InputStreamReader(System.in));
	      }
	 
	      String next() {
	          while (st == null || !st.hasMoreElements()) {
	              try {
	                  st = new StringTokenizer(br.readLine());
	              } catch (IOException e) {
	                  e.printStackTrace();
	              }
	          }
	          return st.nextToken();
	      }
	 
	      int nextInt() {
	          return Integer.parseInt(next());
	      }
	 
	      long nextLong() {
	          return Long.parseLong(next());
	      }
	 
	      double nextDouble() {
	          return Double.parseDouble(next());
	      }
	 
	      String nextLine(){
	          String str = "";
		  try {
		     str = br.readLine();
		  } catch (IOException e) {
		     e.printStackTrace();
		  }
		  return str;
	      }

	   }

}
