```
def main():
    midterm=midtermgra
    final=finalgra
    semgra=semesterGrade(midterm,final)
    category(semgra)
def midtermgra():
    midterm=eval(input('Please enter your midterm grade: '))
    return midterm
def finalgra():
    final=eval(input('Please enter your final grade: '))
    return final
def semesterGrade(midterm,final):
    semgra=(midterm+(final*2))/3
    return semgra
def category(semgra):
    if(semgra<60):
        print('Semester grade: F ')
    elif(semgra<70):
        print('Semester grade: D ')
    elif(semgra<80):
        print('Semester grade: C ')
    elif(semgra<90):
        print('Semester grade: B ')
    else:
        print('Semester grade: A ')
main()

```

I'm trying to coding a structured program following teaching materials. However, it turns out to be a mistake

> 
> TypeError: unsupported operand type(s) for \*: 'function' and 'int''.
> 
> 
> 

I have reread my teaching slides, but can't figure out the problem.
Could anybody help me?