C++ :

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int n,zm[30],c[5][31];
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)
{
	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-1;++i)printf("%d ",zm[i]);
	  printf("%d\n",zm[n-1]);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;
	}
	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 :

var
  a:Array[1..3,1..26]of char;
  b:array['A'..'Z']of longint;
  c:array[0..25]of boolean;
  i,j,n:longint;
function check(x,m:longint):boolean;
var
  yy:boolean;
  i,j:longint;
begin
  if ((b[a[1,x]]+b[a[2,x]]+m)mod n<>b[a[3,x]]) then exit(false);
  for i:=1 to x-1 do
  if (b[a[1,i]]<>-1)and(b[a[2,i]]<>-1)and(b[a[3,i]]<>-1)then
    begin
      yy:=true;
      for j:=0 to 1 do
        if (b[a[1,i]]+b[a[2,i]]+j)mod n=b[a[3,i]] then yy:=false;
      if yy then exit(false);
    end;
  check:=true;
end;
procedure dfs(x,m:longint);
var i,j,d,p,mm:longint;
    aa,bb,cc:boolean;
begin
  if x=0 then
    begin
      if m=0 then
        begin
          for i:=1 to n-1 do write(b[chr(i+64)],' ');
          writeln(b[chr(n+64)]);
          halt;
        end;
      exit;
    end;
  aa:=false;
  bb:=false;
  cc:=false;
  if b[a[1,x]]<>-1 then aa:=true;
  if b[a[2,x]]<>-1 then bb:=true;
  if b[a[3,x]]<>-1 then cc:=true;
  if (aa and bb and cc) then
    begin
      if check(x,m) then dfs(x-1,(m+b[a[1,x]]+b[a[2,x]])div n);
    end
    else if aa and bb then
      begin
        d:=(b[a[1,x]]+b[a[2,x]]+m)mod n;
        if c[d] then
          begin
            b[a[3,x]]:=d;
            c[d]:=false;
            mm:=(b[a[1,x]]+b[a[2,x]]+m)div n;
            if check(x,m) then dfs(x-1,mm);
              c[d]:=true;
              b[a[3,x]]:=-1;
          end;
      end
    else if aa and cc then
  begin
    d:=(b[a[3,x]]-m-b[a[1,x]]+n)mod n;
    if c[d] then
    begin
      b[a[2,x]]:=d;
      c[d]:=false;
      mm:=(d+b[a[1,x]]+m)div n;
      if check(x,m) then dfs(x-1,mm);
      m:=mm;
      c[d]:=true;
      b[a[2,x]]:=-1;
    end;
  end
  else if bb and cc then
    begin
      d:=(b[a[3,x]]-m-b[a[2,x]]+n)mod n;
        if c[d] then
          begin
            b[a[1,x]]:=d;
            c[d]:=false;
            mm:=(d+b[a[2,x]]+m)div n;
            if check(x,m) then dfs(x-1,mm);
            m:=mm;
            c[d]:=true;
            b[a[1,x]]:=-1;
          end;
    end
  else if (not aa)and(not bb)and(not cc) then
    begin
      if a[1,x]<>a[2,x] then
        begin
          for i:=n-1 downto 0 do
            for j:=n-1 downto 0 do
              if (c[i] and c[j])and(i<>j) then
                begin
                  c[i]:=false;
                  c[j]:=false;
                  b[a[1,x]]:=j;
                  b[a[2,x]]:=i;
                  dfs(x,m);
                  c[i]:=true;
                  c[j]:=true;
                  b[a[1,x]]:=-1;
                  b[a[2,x]]:=-1;
                end;
    end
else
for i:=n-1 downto 0 do
if c[i] then
begin
  b[a[1,x]]:=i;
  c[i]:=false;
  dfs(x,m);
  b[a[p,x]]:=-1;
  c[i]:=true;
end;
end
else begin
  for i:=n-1 downto 0 do
  if c[i] then
    begin
      if not aa then p:=1
      else if not bb then p:=2
      else if not cc then p:=3;
      b[a[p,x]]:=i;
      c[i]:=false;
      dfs(x,m);
      b[a[p,x]]:=-1;
      c[i]:=true;
    end;
      end;
end;
begin
  readln(n);
  for i:=1 to 3 do
    begin
      for j:=1 to n do
        read(a[i,j]);
      readln;
    end;
  fillchar(b,sizeof(b),255);
  fillchar(c,sizeof(c),true);
  dfs(n,0);
end.