Marks Grade choiser for class room

#include <stdio.h>

int main() {
    int a;
    int b;
    
    printf("Enter marks from part 1 :");
    scanf("%d",&a);
    
    printf("Enter marks from part 2: ");
    scanf("%d",&b);
    
    int totalMarks =(a+b)/2;
    printf("Total marks of the paper: %d\n",totalMarks);
    
if(totalMarks>=75){
        printf("Grade: A");
    }
    else if(totalMarks>=65){
        printf("Grade: B");
    }else if(totalMarks>=55){
        printf("Grade: C");
    }else if(totalMarks>=35){
        printf("Grade: S");
    }else{
        printf("fail");
    }
    return 0;
}