import java.util.Scanner;

public class WhileMN {
	public static void main(String[] args) {
		try (Scanner scanner = new Scanner(System.in)) {
			System.out.println("请输入M数:");
			int m = scanner.nextInt();
			System.out.println("请输入N数:");
			int n = scanner.nextInt();
			int sum = 0;
			if (m > n) {
				int i = n;
				n = m;
				m = i;
			}
			while (m <= n) {
				sum += m;
				m++;
			}
			System.out.println("M 到 N 求和等于：" + sum);
		}
	}
}