Calculating index for projects

I am working on a Python project for my portfolio, It is allocating projects to students. For this, I am importing data from a file "student_Record.csv". The file has the student's name, last name, marks and 3 project preferences. I want to assign an index to each project before I assign the projects to the students. The index is calculated as Index(P)=50*(Number of Students that put P as 1st preference) + 25*(Number of students that put P as 2nd preference) + 1*(Number of students that put P as 3rd preference)

The sample data in the file looks like Sample data

I have done the following:

import pandas as pd
df = pd.read_csv('sample_data.csv')

project_preferences = {}
for index, row in df.iterrows():
    # Get the student's preferences
    preferences = [row['Pref_1'], row['Pref_2'], row['Pref_3']]
    
    # Assign preference weights to projects
    for preference in preferences:
        project = int(preference)
        
        # Update the project's preference count
        if project not in project_preferences:
            project_preferences[project] = [0, 0, 0]
        project_preferences[project][preferences.index(preference)] += 1

# Calculate Wayne index for each project
wayne_index = {}
for project, preferences in project_preferences.items():
    wayne_index[project] = 50 * preferences[0] + 25 * preferences[1] + preferences[2]

# Print the Wayne index for each project
for project, index in wayne_index.items():
    print(f"Wayne index for Project {project}: {index}")

Am I doing it right?