The Missing Number
Find the one value missing from 0..N using a sum formula.
Input format
The first line has N. The second line has N distinct integers, all from the range 0..N with exactly one value missing.
Output format
Print the one number from 0..N that is missing from the array.
Constraints
- Values fit in a 64-bit signed integer
- Trailing whitespace and a trailing newline are ignored by the judge
Read from stdin, write to stdout. Sample cases below show the exact format.
Sample cases
Example 1
Input
3
0 1 3Expected output
2Example 2
Input
1
0Expected output
1