#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,b; cin>>a; b=a/10; switch(b){ case 10: case 9: cout<<'A';break; case 8: case 7: cout<<'B';break; case 6: cout<<'D';break; default:cout<<a/b;break; } return 0; }