
import java.util.Scanner;

public class Main
{
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		long m=sc.nextLong();
		long ans=0;
		if(n>=2){
			ans+=(n*(n-1))/2;
		}
		if(m>=2){
			ans+=(m*(m-1)/2);
		}
		System.out.println(ans);
	}
} import java.util.Scanner; Scanner java.util public class Main
{
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		long m=sc.nextLong();
		long ans=0;
		if(n>=2){
			ans+=(n*(n-1))/2;
		}
		if(m>=2){
			ans+=(m*(m-1)/2);
		}
		System.out.println(ans);
	}
} Main public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		long m=sc.nextLong();
		long ans=0;
		if(n>=2){
			ans+=(n*(n-1))/2;
		}
		if(m>=2){
			ans+=(m*(m-1)/2);
		}
		System.out.println(ans);
	} main {
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		long m=sc.nextLong();
		long ans=0;
		if(n>=2){
			ans+=(n*(n-1))/2;
		}
		if(m>=2){
			ans+=(m*(m-1)/2);
		}
		System.out.println(ans);
	} Scanner sc=new Scanner(System.in); sc new Scanner(System.in) long n=sc.nextLong(); n sc.nextLong() sc.nextLong sc long m=sc.nextLong(); m sc.nextLong() sc.nextLong sc long ans=0; ans 0 if(n>=2){
			ans+=(n*(n-1))/2;
		} n>=2 n 2 {
			ans+=(n*(n-1))/2;
		} ans+=(n*(n-1))/2 ans (n*(n-1))/2 (n*(n-1)) n (n-1) n 1 2 if(m>=2){
			ans+=(m*(m-1)/2);
		} m>=2 m 2 {
			ans+=(m*(m-1)/2);
		} ans+=(m*(m-1)/2) ans (m*(m-1)/2) m*(m-1) m (m-1) m 1 2 System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main
{
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		long m=sc.nextLong();
		long ans=0;
		if(n>=2){
			ans+=(n*(n-1))/2;
		}
		if(m>=2){
			ans+=(m*(m-1)/2);
		}
		System.out.println(ans);
	}
} public class Main
{
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		long m=sc.nextLong();
		long ans=0;
		if(n>=2){
			ans+=(n*(n-1))/2;
		}
		if(m>=2){
			ans+=(m*(m-1)/2);
		}
		System.out.println(ans);
	}
} Main

import java.util.Scanner;

public class Main
{
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		long n=sc.nextLong();
		long m=sc.nextLong();
		long ans=0;
		if(n>=2){
			ans+=(n*(n-1))/2;
		}
		if(m>=2){
			ans+=(m*(m-1)/2);
		}
		System.out.println(ans);
	}
}
