Homework nested structs

#include <stdio.h>
#include <stdlib.h>

struct Student{
    char name[20];
    float grade;
};

struct Klas{
    unsigned int klasNumber;
    struct Student students[30];
    unsigned int studentsNum;
};

struct Vipusk{
    unsigned int year;
    struct Klas klasove[5];
    unsigned int klasoveNum;
};

float calcAverageKlas(struct Klas klas){
    float sum = 0;

    for(int i = 0; i < klas.studentsNum; i++){
        sum += klas.students[i].grade;
    }

    return sum / klas.studentsNum;
}

float calcAverageVipusk(struct Vipusk* vipusk){
    float sum = 0;
    for(int i = 0; i < vipusk->klasoveNum; i++){
        sum += calcAverageKlas(vipusk->klasove[i]);
    }

    return sum / vipusk->klasoveNum;
}

int main()
{

    struct Vipusk vipusk;

    printf("Enter the number of classes: ");
    scanf("%d", &vipusk.klasoveNum);

    for(int i = 0; i < vipusk.klasoveNum; i++){
        printf("Enter the number of students for class %d: ", i + 1);
        scanf("%d", &(vipusk.klasove[i].studentsNum));
        for(int j = 0; j < vipusk.klasove[i].studentsNum; j++){
            getchar();
            printf("Please enter student name: \n");
            fgets(vipusk.klasove[i].students[j].name, sizeof(vipusk.klasove[i].students[j].name), stdin);
            printf("Please enter the grade: \n");
            scanf("%f", &(vipusk.klasove[i].students[j].grade));

        }
    }

    for (int i = 0; i < vipusk.klasoveNum; i++) {
        printf("Average grade of class %d: %.2f\n", i + 1, calcAverageKlas(vipusk.klasove[i]));
    }

    printf("Average grade of the vipusk: %.2f\n", calcAverageVipusk(&vipusk));

    return 0;
}