#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 n; cin>>n; switch(n){ case n=90+0: case n=90+1: case n=90+2: case n=90+3: case n=90+4: case n=90+5: case n=90+6: case n=90+7: case n=90+8: case n=90+9:cout<<'A';break; case n=80+0: case n=80+1: case n=80+2: case n=80+3: case n=80+4: case n=80+5: case n=80+6: case n=80+7: case n=80+8: case n=80+9: case n=70+0: case n=70+1: case n=70+2: case n=70+3: case n=70+4: case n=70+5: case n=70+6: case n=70+7: case n=70+8: case n=70+9:cout<<'B';break; case n=60+0: case n=60+1: case n=60+2: case n=60+3: case n=60+4: case n=60+5: case n=60+6: case n=60+7: case n=60+8: case n=60+9:cout<<'C';break; break:cout<<'D';break; } return 0; }