Classroom Attendance
The new semester has begun at UptoSkills Arena! The professor needs to take attendance. He has a list of student IDs of students who are present today. However, some students might have accidentally had their ID scanned multiple times. Your task is to help the professor find out how many unique students are present in the classroom. Each student ID is a positive integer.
Input
The first line contains an integer $N$, the total number of ID scans. The second line contains $N$ space-separated positive integers, representing the student IDs scanned.
Output
Print a single integer: the count of unique student IDs.
Constraints
1 <= N <= 1000 1 <= student_ID <= 10^9
Example 1
5 101 102 101 103 102
3
There are 5 ID scans, but only 3 unique IDs (101, 102, 103).
Example 2
3 200 200 200
1
All 3 scans are for the same student ID (200), so there is only 1 unique student.
Hints
# Read the input from stdin and print the answer.
import sys
def main():
data = sys.stdin.read().split()
# your code here
main()
5 101 102 101 103 102
3 200 200 200