import java.util.Scanner;

public class While {

  public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    int m, n;

    System.out.println("这是一个计算两数之间所有自然数的和的程序，请依次输入两个整数,以空格分开");

    m = sc.nextInt();

    n = sc.nextInt();

    int min = Math.min(m, n);

    int max = Math.max(m, n);

    int sum = 0;

    while (min <= max) {

      sum = sum + min;

      min++;

    }

    System.out.printf("%d和%d之间的所有整数和为：%d", m,n, sum) ;

  }

}