C++ :

#include<bits/stdc++.h>
using namespace std;
char str[27];
int book[27],a[27],pd,step,l,c;
void dfs(int ans,int ans_yuan,int ans_fu){
    if(step>=25000)return;
    if(ans==l+1){
        if(ans_yuan>=1&&ans_fu>=2){
            ++step;
            if(pd==1)cout<<endl;
            else pd=1;
            for(int j=1;j<=l;j++)cout<<str[a[j]];
        }
        return;
    }
    for(int i=a[ans-1]+1;i<=c;i++)
        if(book[i]==0){
            book[i]=1;
            a[ans]=i;
            if(str[i]=='a'||str[i]=='e'||str[i]=='i'||str[i]=='o'||str[i]=='u')dfs(ans+1,ans_yuan+1,ans_fu);
            else dfs(ans+1,ans_yuan,ans_fu+1);
            book[i]=0;
        }
}
int main(){
    cin>>l>>c;
    for(int i=1;i<=c;i++)cin>>str[i];
    sort(str+1,str+c+1);
    dfs(1,0,0);
}