graph TD A[Student] --> B{Enter} B -->|Pass| C[End] B -->|Stay| D[After Service] D -->|Leave| E[End] D -->|Stay| F[Target group*]
graph TD A[Student] --> B{Enter} B -->|Pass| C[End] B -->|Stay| D[After Service] D -->|Leave| E[End] D -->|Stay| F[Target group*]