A10693 | PolandBall and Hypothesis
时间限制1s
内存限制256MB
通过 / 提交0/0
题目描述
PolandBall is a young, clever Ball. He is interested in prime numbers. He has stated a following hypothesis: "There exists such a positive integer $n$ that for each positive integer $m$ number $n·m+1$ is a prime number".
Unfortunately, PolandBall is not experienced yet and doesn't know that his hypothesis is incorrect. Could you prove it wrong? Write a program that finds a counterexample for any $n$ .
Unfortunately, PolandBall is not experienced yet and doesn't know that his hypothesis is incorrect. Could you prove it wrong? Write a program that finds a counterexample for any $n$ .
输入格式
The only number in the input is $n$ ( $1<=n<=1000$ ) — number from the PolandBall's hypothesis.
输出格式
Output such $m$ that $n·m+1$ is not a prime number. Your answer will be considered correct if you output any suitable $m$ such that $1<=m<=10^{3}$ . It is guaranteed the the answer exists.
输入输出样例
输入 #1
3
输出 #1
1
输入 #2
4
输出 #2
2
A prime number (or a prime) is a natural number greater than $1$ that has no positive divisors other than $1$ and itself.
For the first sample testcase, $3·1+1=4$ . We can output $1$ .
In the second sample testcase, $4·1+1=5$ . We cannot output $1$ because $5$ is prime. However, $m=2$ is okay since $4·2+1=9$ , which is not a prime number.
For the first sample testcase, $3·1+1=4$ . We can output $1$ .
In the second sample testcase, $4·1+1=5$ . We cannot output $1$ because $5$ is prime. However, $m=2$ is okay since $4·2+1=9$ , which is not a prime number.
C++ 编辑器
输入
输出
可保存默认模板；新题优先使用已保存模板。
当前快捷键仅展示，暂不支持修改。
- 撤销
Ctrl / ⌘ + Z - 重做
Ctrl / ⌘ + Y - 查找
Ctrl / ⌘ + F - 全选
Ctrl / ⌘ + A - 复制
Ctrl / ⌘ + C - 剪切
Ctrl / ⌘ + X - 粘贴
Ctrl / ⌘ + V - 自动排版
工具栏排版按钮 - 草稿保存
编辑时自动保存到本机
历史
提交记录
状态说明时间源码
AI
作答助手
你好，我是作答助手。可以问思路、复杂度、样例含义或代码报错原因；不会直接给出完整 AC 代码。
确定要清空代码吗？
提交通过
评测结果：Accepted