#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

#define N 26
#define A 'A'

char shift( char x, char *key, int pos, int dir )
{
  /* if dir != 0, encrypt; otherwise, decrypt */
  return( A + (N+x+(dir?(key[pos]):(-key[pos])))%N );
}

int main( int argc, char **argv )
{
  char x, *key;
  int i,l,dir;

  if( argc < 3 ) {
    fprintf( stderr, "usage: vigen KEYWORD [1 (encrypt) | 0 (decrypt)]\n" );
    exit(1);
  }

  key = argv[1];
  l   = strlen(key);
  dir = atoi(argv[2]);

  i=0;
  while( (x=getchar()) != EOF ) {
    if( isupper((int) x) ) {
      putchar( shift(x, key, i, dir) );
      i=(i+1)%l;
    } else 
      putchar(x);
  }

  exit(0);
}