10112: ABC350 —— B - Dentist Aoki
[Creator : ]
Description
Takahashi has $N$ teeth, one in each of the holes numbered $1, 2, \dots, N$.
Dentist Aoki will perform $Q$ treatments on these teeth and holes.
In the $i$-th treatment, hole $T_i$ is treated as follows:
- If there is a tooth in hole $T_i$, remove the tooth from hole $T_i$.
- If there is no tooth in hole $T_i$ (i.e., the hole is empty), grow a tooth in hole $T_i$.
After all treatments are completed, how many teeth does Takahashi have?
Dentist Aoki will perform $Q$ treatments on these teeth and holes.
In the $i$-th treatment, hole $T_i$ is treated as follows:
- If there is a tooth in hole $T_i$, remove the tooth from hole $T_i$.
- If there is no tooth in hole $T_i$ (i.e., the hole is empty), grow a tooth in hole $T_i$.
After all treatments are completed, how many teeth does Takahashi have?
Input
The input is given from Standard Input in the following format:
```
$N$ $Q$
$T_1$ $T_2$ $\dots$ $T_Q$
```
```
$N$ $Q$
$T_1$ $T_2$ $\dots$ $T_Q$
```
Output
Print the number of teeth as an integer.
Constraints
- All input values are integers.
- $1 \le N, Q \le 1000$
- $1 \le T_i \le N$
- $1 \le N, Q \le 1000$
- $1 \le T_i \le N$
Sample 1 Input
30 6
2 9 18 27 18 9
Sample 1 Output
28
Initially, Takahashi has 30 teeth, and Aoki performs six treatments.
- In the first treatment, hole 2 is treated. There is a tooth in hole 2, so it is removed.
- In the second treatment, hole 9 is treated. There is a tooth in hole 9, so it is removed.
- In the third treatment, hole 18 is treated. There is a tooth in hole 18, so it is removed.
- In the fourth treatment, hole 27 is treated. There is a tooth in hole 27, so it is removed.
- In the fifth treatment, hole 18 is treated. There is no tooth in hole 18, so a tooth is grown.
- In the sixth treatment, hole 9 is treated. There is no tooth in hole 9, so a tooth is grown.
The final count of teeth is 28.
Sample 2 Input
1 7
1 1 1 1 1 1 1
Sample 2 Output
0
Sample 3 Input
9 20
9 5 1 2 2 2 8 9 2 1 6 2 6 5 8 7 8 5 9 8
Sample 3 Output
5