HDU2004

#include <cstdio>
#include <cstdlib>

int main(){
    int x;
    while(scanf("%d",&x)!=EOF){
        if(x >= 90 && x<= 100)
            printf("A");
        else if(x >= 80&& x<=89)
            printf("B");
        else if(x >= 70 && x <= 79)
            printf("C");
        else if(x >= 60 && x <= 69)
            printf("D");
        else if(x >= 0 && x <= 59)
            printf("E");
        else printf("Score is error!");
        printf("\n");
    }
    return 0;
}