#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ int a; cin>>a; if(a>=90){ cout<<"A"<<endl; }else if(a>=80&&a<90){ cout<<"B"<<endl; }else if(a>=70&&a<80){ cout<<"C"<<endl; }else if(a>=60&&a<70){ cout<<"D"<<endl; }else{ cout<<"E"<<endl; } return 0; }