Gag

Segtree has $ N $ of "gags", each with a value of $ V_i $.

Segtree decided to publish all the gags in any order.

Here, the "joy" you get when you publish the $ i $ th gag to the $ j $ th is expressed as $ V_i --j $.

Find the maximum sum of the "joy" you can get.

input

Input is given from standard input in the following format.

$ N $
$ V_1 $ $ V_2 $ $\$ $ V_N $

output

Please output the maximum value of the sum of "joy". However, the value does not always fit in a 32-bit integer.

Insert a line break at the end.

Constraint

• $1 \ leq N \ leq 10 ^ 5$
• $1 \ leq V_i \ leq 10 ^ 5$
• All inputs are integers.

Input example 1

1
59549

Output example 1

59548

Input example 2

Five
2 1 8 5 7

Output example 2

8

Example

Input

1
59549

Output

59548

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