import java.util.Scanner;
public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int sum = 0;
        if (a + b >= 0 && b >= 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + 1 + i;
            }
        }
        if (a + b > 0 && b < 0) {
            for (int i = 0; i < a; i++) {
                sum += b + (i);
            }
        }
        if (a + b <= 0 && b < 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + (i);
            }
        }
        System.out.println(sum);
    }
} import java.util.Scanner; Scanner java.util public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int sum = 0;
        if (a + b >= 0 && b >= 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + 1 + i;
            }
        }
        if (a + b > 0 && b < 0) {
            for (int i = 0; i < a; i++) {
                sum += b + (i);
            }
        }
        if (a + b <= 0 && b < 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + (i);
            }
        }
        System.out.println(sum);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int sum = 0;
        if (a + b >= 0 && b >= 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + 1 + i;
            }
        }
        if (a + b > 0 && b < 0) {
            for (int i = 0; i < a; i++) {
                sum += b + (i);
            }
        }
        if (a + b <= 0 && b < 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + (i);
            }
        }
        System.out.println(sum);
    } main {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int sum = 0;
        if (a + b >= 0 && b >= 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + 1 + i;
            }
        }
        if (a + b > 0 && b < 0) {
            for (int i = 0; i < a; i++) {
                sum += b + (i);
            }
        }
        if (a + b <= 0 && b < 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + (i);
            }
        }
        System.out.println(sum);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int a = sc.nextInt(); a sc.nextInt() sc.nextInt sc int b = sc.nextInt(); b sc.nextInt() sc.nextInt sc int sum = 0; sum 0 if (a + b >= 0 && b >= 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + 1 + i;
            }
        } a + b >= 0 && b >= 0 a + b >= 0 a + b a b 0 b >= 0 b 0 {
            for (int i = 0; i < a - 1; i++) {
                sum += b + 1 + i;
            }
        } for (int i = 0; i < a - 1; i++) {
                sum += b + 1 + i;
            } int i = 0; int i = 0; i 0 i < a - 1 i a - 1 a 1 i++ i++ i {
                sum += b + 1 + i;
            } {
                sum += b + 1 + i;
            } sum += b + 1 + i sum b + 1 + i b + 1 + i b 1 i if (a + b > 0 && b < 0) {
            for (int i = 0; i < a; i++) {
                sum += b + (i);
            }
        } a + b > 0 && b < 0 a + b > 0 a + b a b 0 b < 0 b 0 {
            for (int i = 0; i < a; i++) {
                sum += b + (i);
            }
        } for (int i = 0; i < a; i++) {
                sum += b + (i);
            } int i = 0; int i = 0; i 0 i < a i a i++ i++ i {
                sum += b + (i);
            } {
                sum += b + (i);
            } sum += b + (i) sum b + (i) b (i) if (a + b <= 0 && b < 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + (i);
            }
        } a + b <= 0 && b < 0 a + b <= 0 a + b a b 0 b < 0 b 0 {
            for (int i = 0; i < a - 1; i++) {
                sum += b + (i);
            }
        } for (int i = 0; i < a - 1; i++) {
                sum += b + (i);
            } int i = 0; int i = 0; i 0 i < a - 1 i a - 1 a 1 i++ i++ i {
                sum += b + (i);
            } {
                sum += b + (i);
            } sum += b + (i) sum b + (i) b (i) System.out.println(sum) System.out.println System.out System System.out sum String[] args args public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int sum = 0;
        if (a + b >= 0 && b >= 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + 1 + i;
            }
        }
        if (a + b > 0 && b < 0) {
            for (int i = 0; i < a; i++) {
                sum += b + (i);
            }
        }
        if (a + b <= 0 && b < 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + (i);
            }
        }
        System.out.println(sum);
    }
} public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int sum = 0;
        if (a + b >= 0 && b >= 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + 1 + i;
            }
        }
        if (a + b > 0 && b < 0) {
            for (int i = 0; i < a; i++) {
                sum += b + (i);
            }
        }
        if (a + b <= 0 && b < 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + (i);
            }
        }
        System.out.println(sum);
    }
} Main
import java.util.Scanner;
public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        int sum = 0;
        if (a + b >= 0 && b >= 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + 1 + i;
            }
        }
        if (a + b > 0 && b < 0) {
            for (int i = 0; i < a; i++) {
                sum += b + (i);
            }
        }
        if (a + b <= 0 && b < 0) {
            for (int i = 0; i < a - 1; i++) {
                sum += b + (i);
            }
        }
        System.out.println(sum);
    }
}