int dfs(int step,bool &state)//1:to check
{
    int res;
    if (step<m-1) res=dfs(step+1,state);
    int pos=n-vec[step]-1;
    cout<<step<<' '<<str[vec[step]]<<' '<<str[pos]<<endl;
    for(char ch='a';ch<='z';ch++)
        if (state&&str[pos]==ch)
        {
            if (ch<'z') continue;
            else return -1;//error
        }
        else
        {
            str[vec[step]]=ch;
            if (state&&str[pos]!='?'&&ch!=str[pos]) state=0;
            if (ch!=str[pos]) return 1;
        }
    return -1;
}

#include<cctype>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
#include<string>
#include<queue>
#include<stack>
#include<set>
#include<map>
#define CLEAR(a) memset((a),0,sizeof((a)))

using namespace std;

typedef long long LL;
const double pi = acos(-1.0);
const int maxn=2e3;
const int inf=99999999;
const float eps=1e-3;

vector<int> vec;
int n,m;
char s[maxn],str[maxn];

int dfs(int step,bool &state)//1:to check
{

    int pos=n-vec[step]-1;
    for(char ch='a';ch<='z';ch++)
        {
            str[vec[step]]=ch;
            if (str[pos]!='?'&&ch!=str[pos]) {state=0;}
            if (step<m-1) dfs(step+1,state);
            if (state&&str[pos]!='?'&&ch!=str[pos]||!state) return 1;
        }

    return -1;
}

int main()
{

    while(~scanf("%d",&n))
    {
        vec.clear();
        scanf("%s",s);
        memcpy(str,s,sizeof(s));
        for(int i=0;i<n;i++)
            if (s[i]=='?')
                vec.push_back(i);
        m=vec.size();
        bool tmp=1;

        if (m>1||m==1&&!(n%2&&vec[0]==n/2))
        {
            if (dfs(0,tmp)>=0) puts(str);
            else puts("QwQ");
        }
        else
        {
            bool ans=1;
            for(int i=1;i<=strlen(s)/2;i++)
                if (s[i-1]!=s[strlen(s)-i])
                {
                    ans=0;break;
                }
            if (m==1&&n%2&&vec[0]==n/2) str[vec[0]]='a';
            puts(ans?"QwQ":str);
        }

    }
    return 0;
}

// 线段树
#include <stdio .h>
#include <string .h>
#include <stdlib .h>
#define MAX 51000
#define MID(a,b) (a+b)>>1
#define R(a) (a< <1|1)
#define L(a) a<<1
typedef struct {
    int num,left,right;
}Node;
int ans[MAX];
Node Tree[MAX<<2];
int n;

void Build(int t,int l,int r)         //以1为根节点建立线段树
{
    int mid;
    Tree[t].left=l,Tree[t].right=r;
    if(Tree[t].left==Tree[t].right)
    {
        Tree[t].num=0;
        return ;
    }
    mid=MID(Tree[t].left,Tree[t].right);
    Build(L(t),l,mid);
    Build(R(t),mid+1,r);
}

void Insert(int t,int l,int r,int x)     //向以1为根节点的区间[l,r]插入数字1
{
    int mid;
    if(Tree[t].left==l&&Tree[t].right==r)
    {
        Tree[t].num+=x;
        return ;
    }
    mid=MID(Tree[t].left,Tree[t].right);
    if(l>mid)
    {
        Insert(R(t),l,r,x);
    }
    else if(r< =mid)
    {
        Insert(L(t),l,r,x);
    }
    else
    {
        Insert(L(t),l,mid,x);
        Insert(R(t),mid+1,r,x);
    }
    Tree[t].num=Tree[L(t)].num+Tree[R(t)].num;
}

int Query(int t,int l,int r)           //查询以1为根节点，区间[l,r]的和
{
    int mid;
    if(Tree[t].left==l&&Tree[t].right==r)
        return Tree[t].num;
    mid=MID(Tree[t].left,Tree[t].right);
    if(l>mid)
    {
        return Query(R(t),l,r);
    }
    else if(r<=mid)
    {
        return Query(L(t),l,r);
    }
    else
    {
        return Query(L(t),l,mid)+Query(R(t),mid+1,r);
    }
}


int main()
{
    int a,n,i,t;
    scanf("%d",&t);
    long long int k;
    while(t--)
    {
        scanf("%d",&n);
        memset(Tree,0,sizeof(Tree));  //初始化线段树
        Build(1,1,n);
        for(i=1;i<=n;i++)             //输入n个数
        {
            scanf("%d",&ans[i]);
        }
        for(i=1,k=0;i<=n;i++)
        {
            a=ans[i];
            Insert(1,a,a,1);          //把线段树[ans[i],ans[i]]区间的值插入为1
            k=k+(i-Query(1,1,a));     //查询区间[1,ans[i]]值的总和,逆序数等于i-[1,ans[i]]
        }
        printf("%lld\n",k);
    }
    return 0;
}

// 树状数组
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <algorithm>
using namespace std;
#define MAX 100010
int c[MAX],a[MAX],ans[MAX],n;

int Lowbit(int x)      //返回二进制最后一个1所表示的数
{
  return x&(-x);
}

void Updata(int x)     //向前更新
{
  while(x<=n)
  {
    c[x]++;
    x+=Lowbit(x);
  }
}

int Sum(int x)         //向后更新求和
{
  int sum=0;
  while(x>0)
  {
    sum+=c[x];
    x-=Lowbit(x);
  }
  return sum;
}

int main()
{
  int i,t,k;
    scanf("%d",&t);
  while(t--)
  {
        scanf("%d",&n);
        for(i=1;i<=n;i++)
    {
      scanf("%d",&ans[i]);
    }
    memset(c,0,sizeof(c));        //初始化树状数组
    for(i=1,k=0;i<=n;i++)
    {
      Updata(ans[i]);         //向后更新节点ans[i].k
      k=k+(i-Sum(ans[i]));    //向前查询节点ans[i].k
    }
    printf("%d\n",k);
  }
  return 0;
}