{"raw_statement":[{"iden":"statement","content":"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_\".\n\nUnfortunately, 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_."},{"iden":"input","content":"The only number in the input is _n_ (1 ≤ _n_ ≤ 1000) — number from the PolandBall's hypothesis."},{"iden":"output","content":"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_ ≤ 103. It is guaranteed the the answer exists."},{"iden":"examples","content":"Input\n\n3\n\nOutput\n\n1\n\nInput\n\n4\n\nOutput\n\n2"},{"iden":"note","content":"A prime number (or a prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself.\n\nFor the first sample testcase, 3·1 + 1 = 4. We can output 1.\n\nIn 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."}],"translated_statement":[{"iden":"statement","content":"PolandBall 是一个年轻聪明的球，他对质数感兴趣。他提出了以下假设：\"存在一个正整数 #cf_span[n]，使得对于每个正整数 #cf_span[m]，数 #cf_span[n·m + 1] 都是质数\"。\n\n不幸的是，PolandBall 还缺乏经验，不知道他的假设是错误的。你能证明它错误吗？请编写一个程序，为任意 #cf_span[n] 找出一个反例。\n\n输入中唯一的数字是 #cf_span[n] (#cf_span[1 ≤ n ≤ 1000]) —— 来自 PolandBall 假设的数。\n\n请输出一个 #cf_span[m]，使得 #cf_span[n·m + 1] 不是质数。只要输出任意满足 #cf_span[1 ≤ m ≤ 103] 的合适 #cf_span[m]，你的答案就会被视为正确。保证答案存在。\n\n质数（或称素数）是大于 #cf_span[1] 的自然数，且除了 #cf_span[1] 和它本身之外没有其他正因数。\n\n对于第一个样例测试用例，#cf_span[3·1 + 1 = 4]。我们可以输出 #cf_span[1]。\n\n在第二个样例测试用例中，#cf_span[4·1 + 1 = 5]。我们不能输出 #cf_span[1]，因为 #cf_span[5] 是质数。但 #cf_span[m = 2] 是可以的，因为 #cf_span[4·2 + 1 = 9]，而 9 不是质数。"},{"iden":"input","content":"输入中唯一的数字是 #cf_span[n] (#cf_span[1 ≤ n ≤ 1000]) —— 来自 PolandBall 假设的数。"},{"iden":"output","content":"请输出一个 #cf_span[m]，使得 #cf_span[n·m + 1] 不是质数。只要输出任意满足 #cf_span[1 ≤ m ≤ 103] 的合适 #cf_span[m]，你的答案就会被视为正确。保证答案存在。"},{"iden":"examples","content":"输入\n3\n输出\n1\n输入\n4\n输出\n2"},{"iden":"note","content":"质数（或称素数）是大于 #cf_span[1] 的自然数，且除了 #cf_span[1] 和它本身之外没有其他正因数。对于第一个样例测试用例，#cf_span[3·1 + 1 = 4]。我们可以输出 #cf_span[1]。在第二个样例测试用例中，#cf_span[4·1 + 1 = 5]。我们不能输出 #cf_span[1]，因为 #cf_span[5] 是质数。但 #cf_span[m = 2] 是可以的，因为 #cf_span[4·2 + 1 = 9]，而 9 不是质数。"}],"sample_group":[],"show_order":[],"formal_statement":"**Definitions**  \nLet $ n \\in \\mathbb{Z} $ with $ 1 \\leq n \\leq 1000 $.  \n\n**Objective**  \nFind an integer $ m \\in \\mathbb{Z} $ such that $ 1 \\leq m \\leq 10^3 $ and $ nm + 1 $ is composite.  \n\n**Constraint**  \n$ nm + 1 $ is not prime.","simple_statement":null,"has_page_source":false}