C++ :

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int n,zm[30],c[31][5];
char c1;
bool f[30],F;
bool jc()
{
	int p=0;
	for(int i=n-1;i>=0;--i)
	{
	  if (zm[c[1][i]]==-1||zm[c[2][i]]==-1||zm[c[3][i]]==-1)return false;
	  int x=zm[c[1][i]]+zm[c[2][i]]+p;
	  if(x%n!=zm[c[3][i]])return true;
	  p=x/n;
	}
	return false;
}
bool jc2()
{
	for(int i=n-1;i>=0;--i)//a+b?c
	  if(zm[c[1][i]]!=-1&&zm[c[2][i]]!=-1&&zm[c[3][i]]!=-1)
	  {
		int x=(zm[c[1][i]]+zm[c[2][i]])%n;
		if(!(x%n==zm[c[3][i]]||(x+1)%n==zm[c[3][i]]))return true;
	  }
	for(int i=n-1;i>=0;--i)//a+?=c
	  if(zm[c[1][i]]!=-1&&zm[c[2][i]]==-1&&zm[c[3][i]]!=-1)
	  {
		int x=(zm[c[3][i]]-zm[c[1][i]]+n)%n;
		if(f[x]&&f[(x-1)%n])return true;
	  }
	for(int i=n-1;i>=0;--i)//?+b=c
	  if(zm[c[1][i]]==-1&&zm[c[2][i]]!=-1&&zm[c[3][i]]!=-1)
	  {
		int x=(zm[c[3][i]]-zm[c[2][i]]+n)%n;
		if(f[x]&&f[(x-1)%n])return true;
	  }
	for(int i=n-1;i>=0;--i)//a+b=?
	  if(zm[c[1][i]]!=-1&&zm[c[2][i]]!=-1&&zm[c[3][i]]==-1)
	  {
		int x=(zm[c[1][i]]+zm[c[2][i]])%n;
		if(f[x]&&f[(x+1)%n])return true;
	  }
	return false;
}
void work(int k,int w)
{
	//printf("%d %d\n",k,w);
	//	for(int i=0;i<n;++i)printf("%d ",zm[i]);printf("\n");
	if(F)return;
	if(jc())return;
	if(jc2())return;
	//if(zm[c[1][0]-65]+zm[c[2][0]-65]>n)return;
	if(k==0&&w==3)
	{
	  for(int i=0;i<n;++i)printf("%d ",zm[i]);
	  printf("\n");F=true;return;
	}
	
	
	if(zm[c[w][k]]!=-1)
	{
	  if(w==3){w=1;--k;}else ++w;
	  work(k,w);
	  if(w==1){w=3;++k;}else --w;
	}//printf("%d %d\n",k,w);
	else
	{
	  for(int i=n-1;i>=0;--i)
	    if(!f[i])
	    {
		  zm[c[w][k]]=i,f[i]=true;
		  if(w==3){w=1;--k;}else ++w;
		  work(k,w);
		  if(w==1){w=3;++k;}else --w;
		  zm[c[w][k]]=-1;f[i]=false;
	    }
	}
	
}
int main()
{
	memset(c,0,sizeof(c));
	scanf("%d",&n);
	for(int i=1;i<=3;++i)
	  for(int j=0;j<n;++j)
	    {cin>>c1;c[i][j]=c1-65;}
	F=false;
	memset(f,0,sizeof(f));
	for(int i=0;i<n;++i)zm[i]=-1;
	work(n-1,1);
	return 0;
}

Pascal :

program alpha;
var i,j,k,n:longint;
st1,st2,st3 :string;
a :array['A'..'Z']of longint;
s,vis :array[0..30]of longint;
function data(i:longint):boolean;
var k :longint;
 begin
  for k:=i downto 1 do
  if (a[st1[k]]>-1)and(a[st2[k]]>-1)and(a[st3[k]]>-1) then
  if ((a[st1[k]]+a[st2[k]])mod n<>a[st3[k]])and
  ((a[st1[k]]+a[st2[k]]+1)mod n<>a[st3[k]]) then exit(true);
  if (a[st1[k]]>-1)and(a[st2[k]]>-1) then
  if a[st1[k]]+a[st2[k]]>n then exit(true);
  if (a[st1[k]]>-1)and(a[st2[k]]>-1)and(a[st3[k]]>-1) then
  if ((a[st1[k]]+a[st2[k]]+1)mod n=a[st3[k]])
  and(a[st1[k]]+a[st2[k]]+1>n) then exit(true);
  exit(true);
 end;

procedure dfs(k,j,g:longint);
var i,p:longint;
 begin
  if k=0 then
  if j=0 then
  begin
   for i:=1 to n-1 do
    write(a[chr(ord('A')+i-1)],' ');
    writeln(a[chr(ord('A')+n-1)]);
    halt;
  end else exit;
  if a[st1[k]]=-1 then
   begin
    if (a[st2[k]]=-1)or(a[st3[k]]=-1) then
    for i:=1 to g do
     begin
      a[st1[k]]:=s[i];
      vis[s[i]]:=g;
      s[i]:=s[g];
      vis[s[i]]:=i;
      if data(k) then dfs(k,j,g-1);
      vis[s[i]]:=g;
      s[i]:=a[st1[k]];
      vis[s[i]]:=i;
     end else
    begin
     a[st1[k]]:=a[st3[k]]-a[st2[k]]-j;
     if a[st1[k]]<0 then
      begin
       p:=1;
       a[st1[k]]:=a[st1[k]]+n;
      end else p:=0;
     i:=vis[a[st1[k]]];
     if i<=g then
      begin
       s[i]:=s[g];
       vis[a[st1[k]]]:=g;
       vis[s[i]]:=i;
       if data(k) then
       if p=1 then dfs(k-1,1,g-1) else dfs(k-1,0,g-1);
       vis[s[i]]:=g;
       vis[a[st1[k]]]:=i;
       s[i]:=a[st1[k]];
      end;
    end;
    a[st1[k]]:=-1;
    exit;
   end;
  if a[st2[k]]=-1 then
  begin
   if (a[st1[k]]=-1)or(a[st3[k]]=-1) then
   for i:=1 to g do
   begin
    a[st2[k]]:=s[i];
    vis[s[i]]:=g;
    s[i]:=s[g];
    vis[s[i]]:=i;
    if data(k) then
    dfs(k,j,g-1);
    vis[s[i]]:=g;
    s[i]:=a[st2[k]];
    vis[s[i]]:=i;
   end else
  begin
   a[st2[k]]:=a[st3[k]]-a[st1[k]]-j;
   if a[st2[k]]<0 then
   begin
    p:=1;
    a[st2[k]]:=a[st2[k]]+n;
   end else p:=0;
  i:=vis[a[st2[k]]];
  if i<=g then
   begin
    s[i]:=s[g];
    vis[a[st2[k]]]:=g;
    vis[s[i]]:=i;
    if data(k) then
    if p=1 then dfs(k-1,1,g-1) else dfs(k-1,0,g-1);
    vis[s[i]]:=g;
    vis[a[st2[k]]]:=i;
    s[i]:=a[st2[k]];
   end;
  end;
  a[st2[k]]:=-1;
  exit;
 end;
 if a[st3[k]]=-1 then
 begin
  a[st3[k]]:=(a[st1[k]]+a[st2[k]]+j)mod n;
  i:=vis[a[st3[k]]];
  if i<=g then
   begin
    s[i]:=s[g];
    vis[s[g]]:=i;
    vis[a[st3[k]]]:=g;
    if data(k) then
    dfs(k-1,(a[st1[k]]+a[st2[k]]+j)div n,g-1);
    vis[a[st3[k]]]:=i;
    vis[s[g]]:=g;
    s[i]:=a[st3[k]];
   end;
  a[st3[k]]:=-1;
 end else if a[st3[k]]=(a[st1[k]]+a[st2[k]]+j)mod n then
  dfs(k-1,(a[st1[k]]+a[st2[k]]+j)div n,g);
 end;
 begin
  readln(n);
  readln(st1);
  readln(st2);
  readln(st3);
  for i:=1 to n do a[chr(ord('A')+i-1)]:=-1;
   for i:=1 to n do
    begin
     s[i]:=n-i;
     vis[n-i]:=i;
    end;
  dfs(n,0,n);
end.