#include<iostream>
using namespace std;
class student{
    public:
    string name;
    string subject;
    int mark;
    student(string name,string subject,int mark){
        this->name=name;
        this->subject=subject;
        this->mark=mark;
    }
    void displayGrade(){
        cout<<"Name"<<name<<endl;
        cout<<"subject"<<subject<<endl;
        cout<<"Mark"<<mark<<endl;
        if(mark>=90){
            cout<<"Grade: A"<<endl;
        }
        else if (mark=75&&mark<90){
            cout<<"Grade: B"<<endl; 
        }
        else if(mark>=50&&mark<75){
            cout<<"Grade: C"<<endl;
        }
        else{
            cout<<"Grade: F"<<endl;
        }
    }
};
int main(){
    string name,subject;
    int mark;
    cin>>name>>subject>>mark;
    cout<<"Invalid input";
    return 0;
}
student*obj=new student(name,subject,mark);
obj->displayGrade();