int main(){
    int age,marks;
    printf("enter your age\n");
    scanf("%d",&age);
    
    printf("enter your marks\n");
    scanf("%d",&marks);
    
    switch(age){
        case 3:
            printf("the age is 3\n");
            switch(marks){
                case 45:
                    printf("your marks are 45");
                    break;
                    
                default:
                    printf("your marks are not 45");
            }
        break;
        
        case 13:
            printf("the age is 13\n");
        break;
        
        case 23:
            printf("the age is 23\n");
        break;
        
        default:
            printf("age is not 3,13 or 23\n");
        
    }
    return 0;
}