#include<stdio.h>

int main()
{
  int shift = 0;char choice;
  printf("Enter the shift parameter ( < 26 )");
  scanf("%d",&shift);
  //while((ch))
  printf("Enter 'e' for encrypt or 'd' for decrypt :");
  scanf(" %c",&choice); // note the space before %c
  printf("shift : %d  choice : %c \n",shift,choice);
  char ch;
  while( (ch = getchar()) != '\n' );
  
  ch = getchar();
  //int isNegative = 0,gotDecimal = 0;int integerPart = 0,floatPart = 0,div1 = 1,div =1;
  while( (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') )
  {
    if(choice == 'e')
    {
      if(ch >= 'a' && ch<='z')
      {
	int offset = ( (ch - 'a')+shift )% 26;
	putchar('a' + offset);
      }
      if(ch >= 'A' && ch<='Z')
      {
	int offset = ( (ch - 'A')+shift )% 26;
	putchar('A' + offset);
      }
    }
    else if(choice == 'd')
    {
      if(ch >= 'a' && ch<='z')
      {
	int offset = ( (ch - 'a')-shift )% 26;
	if(offset < 0)
	  offset = offset + 26;
	putchar('a' + offset);
      }
      if(ch >= 'A' && ch<='Z')
      {
	int offset = ( (ch - 'A')-shift )% 26;
	putchar('A' + offset);
      }
    }
    
    ch = getchar();
  }
 
  printf("\n");
  return 0;
}