#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 score; cin>>score; if(score>=90){ cout<<'A'; }else if((80<=score)&&(score<90)){ cout<<'B'; }else if((70<=score)&&(score<80)){ cout<<'C'; }else if((60<=score)&&(score<70)){ cout<<'D'; }else{ cout<<'E'; } return 0; }