#include <stdio.h>

int main() {
    int marks;
    printf("enter marks \n");
    scanf(" %d", &marks);
    if (marks <30){
        printf(" C");
    }else if (30 <= marks < 70 )
    { printf (" B ");
    } else if(70 <= marks < 90)
    { printf(" A ");
    } else 
    { printf(" A + ");
        
    }
    
    return 0;
}