// Online C compiler to run C program online
#include <stdio.h>

int main() {
   int size = 5;
   int a[size];
   for(int i = 0;i < size;i++){
       printf("Student - %d: ",i+1);
       scanf("%d",&a[i]);
   }
   for(int i =0;i < size;i++){
       if(a[i]>85){
           a[i] = 'A';
       }
       else if(a[i]>70){
           a[i] = 'B';
       }
       else if(a[i]>60){
           a[i] = 'C';
       }
       else if(a[i]<=50){
           a[i] = 'F';
       }
   }
   for(int i = 0; i < size; i++){
       printf("%c",a[i]);
   }
    

    return 0;
}