codeforces 753 A. Dasha and Stairs

最新推荐文章于 2023-04-27 00:48:42 发布

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本文介绍了一个关于计算楼梯上偶数和奇数台阶数量的简单编程问题。通过输入偶数台阶和奇数台阶的数量，判断是否存在一个区间使得这两个数值正确。文章提供了一个C语言的解决方案，并附带了解题思路。

A. Dasha and Stairs

time limit per test

2 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

On her way to programming school tiger Dasha faced her first test — a huge staircase!

$\text{[math]}$

The steps were numbered from one to infinity. As we know, tigers are very fond of all striped things, it is possible that it has something to do with their color. So on some interval of her way she calculated two values — the number of steps with even and odd numbers.

You need to check whether there is an interval of steps from the l-th to the r-th (1 ≤ l ≤ r), for which values that Dasha has found are correct.

Input

In the only line you are given two integers a, b (0 ≤ a, b ≤ 100) — the number of even and odd steps, accordingly.

Output

In the only line print “YES“, if the interval of steps described above exists, and “NO” otherwise.

Examples

Input

2 3

Output

YES

Input

3 1

Output

NO

Note

In the first example one of suitable intervals is from 1 to 5. The interval contains two even steps — 2 and 4, and three odd: 1, 3 and 5.

水题，把等于0的情况考虑下就AC了

#include<stdio.h>
int abs(int x) {
    if(x < 0)
    return -x;
return x;
}

int main()
{
    int a, b;
    while(~scanf("%d%d",&a,&b)) {
        if(a == 0 && b == 0) 
            printf("NO\n");
        else {
            if(abs(a-b) > 1) 
                printf("NO\n");
            else
            printf("YES\n");
        }
    }
return 0;
 }