Keep getting type error: Can only concatenate str $($not "int"$)$ to str$.$

Heres the code:

def toFixed$($value$,$ digits$)$:

return $"\%.*$f$"\%($digits$,$ value$)$

print$("$Enter the amount of students:"$)$

amountOfStudents $=$ int$($input$())$

studentsList $=[""]*($amountOfStudents$)$

gradesList $=[0]*($amountOfStudents$)$

total $=0$

highest $=0$

saveHighestIndex $=0$

lowest $=100$

saveLowestIndex $=0$

for i in range$(0,$ amountOfStudents $-1+1,1)$:

print$("$Enter a last name for student" $+($i $+1)+"$:$")$

lastName $=$ input$()$

studentsList$[$i$]=$ lastName

print$("$Enter a grade for student" $+($i $+1)+"$:$")$

grade $=$ int$($input$())$

gradesList$[$i$]=$ grade

for i in range$(0,$ amountOfStudents $-1+1,1)$:

if gradesList$[$i$]>$ highest:

highest $=$ gradesList$[$i$]$

saveHighestIndex $=$ i

if gradesList$[$i$]<$ lowest:

lowest $=$ gradesList$[$i$]$

saveLowestIndex $=$ i

total $=$ total $+$ gradesList$[$i$]$

print$("$The students and grades entered are:"$)$

for i in range$(0,$ amountOfStudents $-1+1,1)$:

print$($studentsList$[$i$]+""+$ gradesList$[$i$])$

print$("$Average:$"+""+$ toFixed$($total $/$ amountOfStudents,$1))$

print$("$Highest:$"+""+$ gradesList$[$saveHighestIndex$]+""+$ studentsList$[$saveHighestIndex$])$

print$("$Lowest:$"+""+$ gradesList$[$saveLowestIndex$]+""+$ studentsList$[$saveLowestIndex$])$

Additionally would like my code to look like:

Enter the amount of students: $5$

Enter a last name and grade: Davis $78$

Enter a last name and grade: Jones $98$

Enter a last name and grade: Larson $100$

Enter a last name and grade: Moris $54$

Enter a last name and grade:Smith $88$

The students and grades entered are

Davis $78$

Jones $98$

Larson $100$

Morris $54$

Smith $88$

Average: $83\mathrm{.}6$

Highest: $100$ Larson

Lowest: $54$ Morris

Rather than it asking me the name, input. Then the grade.