#include <stdio.h>

int main(){  
 int marks;
 printf(" please enter number: ");
 scanf ("%d",&marks);
 marks>90 ? printf("your grade is A")
:(marks>=75)? printf("your grade is B")
:(marks>=50)? printf("yor grade is c")  
:(marks>=30)? printf("your grade is D")
:printf("you fail the exame");
  return 0; 
}