Help Ankur To Win The Game Ankur is playing a game with Deepika. Rule of game is described below:- There are N jars. Each jar contains 1 or more ball(s). During each turn, a player selects a jar and takes out 1 or more ball(s).The last player to take out the last ball(s) wins the game. Ankur makes a modification to the game because hi is bored . For the first 50 moves,the game is played in the following manner: Step1: - Ankur adds a jar contaning a non-zero number of balls. Step2:- Deepika adds a jar contaning a non-zero number of balls. Step3:- Ankur sleects a jar and takes out 1 or more balls. Step4:- Deepika selects a jar and takes out 1 or more balls. After the first 50 moves, the usual rules of the game are followed, and the addition of jars does not takes place. Ankur plays first . Ankur wants to know the minimum number of balls the first additional jar should contain (which he is adding in the first turn of the game ) in order for him to win. If no such jar exists,print -1. Find the minimum number of balls Ankur should add to win the game. INPUT: The first line contains an integer N, denoting the number of jars. The next contains N integer. The ith integer denotes the number of balls in the ith jar.. OUTPUT: Print the answer CONSTRAINTS:- 1<=N<=1000 1<=Number of balls in any jar <= 10^5. Sample Input:- 1 10 Sample Output:- 10