PUCMM334 - White Hats

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There is a number of people in a room (between 2 and 100), and each of them wears a hat which is either black or white. Every person counts the number of other people wearing white hats. You are given the number counted by each person. Print the total number of people wearing white hats, or -1 if count doesn't correspond to a valid situation.

Input

The first line is N, the number of persons.

Then N space separaten integers follow, each one denoting the number of white hats each person sees.

Output

Print the total number of people wearing white hats, or -1 if count doesn't correspond to a valid situation.

Example

Input:                              Output:
3 2
2 1 1

Input:
Output:
3 3
2 2 2

Input:
Output:
2 0
0 0

Input: Output:
2 -1
10 10

hide comments
iloveaakanksha: 2016-06-25 05:42:58

Weaker test cases than CRLAVEN.

mkfeuhrer: 2016-06-21 22:53:12

CRNVALEN - same !!

cute_girl_1: 2016-01-29 16:23:00

forgot to delete scanf statement of crnvalen prob caused ce :(

xpshekhar: 2016-01-03 04:37:33

lots of boundary cases make this problem not that easy.
Good One!!

anuveshkothari: 2015-07-14 08:31:25

same code as The Valentine Confession
only number of testcases is 1..

Akshat Mathur: 2015-06-26 11:49:45

Take care of this-
i/p -> 2 2 1 1 2 1
o/p -> -1

:.Mohib.:: 2015-05-09 20:21:03

Easy.....AC... :)

ROHIT RAJ: 2015-02-12 15:52:02

similar to CRNVALEN :)

/* EDWARD KENWAY */: 2014-02-26 21:12:16

there r some hidden/tricky cases for
o/p = -1
otherwise the problem is pretty straight forward

parbays: 2014-01-31 21:17:07

@Doshi, check for the boundary cases.
one TC:
2
1 0
o/p: 1


Added by:Olson Ortiz
Date:2013-01-01
Time limit:0.184s
Source limit:50000B
Memory limit:1536MB
Cluster: Cube (Intel G860)
Languages:All except: ASM32-GCC MAWK BC C-CLANG CPP14-CLANG CPP14 COBOL COFFEE D-DMD D-CLANG DART ELIXIR FANTOM FORTH GOSU GRV JS-MONKEY KTLN NIM OBJC OBJC-CLANG OCT PICO PROLOG PYPY R RACKET RUST CHICKEN SQLITE SWIFT UNLAMBDA VB.NET
Resource:Olimpiada de ProgramaciĆ³n PUCMM ACM-ISC 2013