#include <string.h>

int main ()
{
  char str[][5] = { "R2D2" , "C3PO" , "R2A6" };
  int n, found = 0;
  
  for (n=0 ; n<3 ; n++)
    if (strncmp (str[n],"R2xx",2) == 0)
      found++;

  assert(found != 2);
  return 0;
}
