#P4887. Initial Bet
Initial Bet
Initial Bet
题面翻译
有五个人在玩游戏 每个人一开始有 个硬币 有一种操作是把一个硬币给另一个人 给你所有人经过若干次操作的硬币数 ()求正整数 ,若无解输出 。
题目描述
There are five people playing a game called "Generosity". Each person gives some non-zero number of coins as an initial bet. After all players make their bets of coins, the following operation is repeated for several times: a coin is passed from one player to some other player.
Your task is to write a program that can, given the number of coins each player has at the end of the game, determine the size of the initial bet or find out that such outcome of the game cannot be obtained for any positive number of coins in the initial bet.
输入格式
There are five people playing a game called "Generosity". Each person gives some non-zero number of coins as an initial bet. After all players make their bets of coins, the following operation is repeated for several times: a coin is passed from one player to some other player.
Your task is to write a program that can, given the number of coins each player has at the end of the game, determine the size of the initial bet or find out that such outcome of the game cannot be obtained for any positive number of coins in the initial bet.
输出格式
Print the only line containing a single positive integer — the number of coins in the initial bet of each player. If there is no such value of , then print the only value "-1" (quotes for clarity).
样例 #1
样例输入 #1
2 5 4 0 4
样例输出 #1
3
样例 #2
样例输入 #2
4 5 9 2 1
样例输出 #2
-1
提示
In the first sample the following sequence of operations is possible:
- One coin is passed from the fourth player to the second player;
- One coin is passed from the fourth player to the fifth player;
- One coin is passed from the first player to the third player;
- One coin is passed from the fourth player to the second player.