C++ :

#include <iostream>
#include <string>
#include <limits.h>
#include <cstdio>
using namespace std;
string s[25];
char c;
int vis[25];
int m = 0, n;
void dfs(string a, int sum)
{
    //cout<<sum<<endl;
    for (int i=0; i<n; i++)
    {
        if (vis[i]<2)
        {
            //cout<<a<<" "<<s[i]<<endl;
            int j, t=0, k, max=0;
            for (j=1; j<=s[i].size(); j++)
            {
                for (k=a.size()-j, t=0; k<a.size() && t<j; t++, k++)
                    if (a[k]!=s[i][t]) break;
                if (k==a.size()) {max = j; break;}
            }
            if (max==0) continue;
            vis[i]++;
            dfs(s[i], sum + a.size()-max);
            vis[i]--;
        }
    }
    sum+=a.size();
    if (sum>m) m = sum;
}
int main()
{
    //freopen("in.txt", "r", stdin);
    //freopen("out.txt", "w", stdout);
    cin>>n;
    for (int i=0; i<n; i++)
        cin>>s[i];
    cin>>c;
    for (int i=0; i<n; i++)
        if (s[i][0]==c){
            vis[i]++;
            dfs(s[i], 0);
            vis[i]--;
        }
    cout<<m<<endl;
    return 0;
}

Pascal :

var st:array[1..20]of ansistring;
    a:array[1..20,1..20]of longint;
    b:array[1..20]of longint;
    i,j,n,max:longint;
    ch:char;maxst:ansistring;
function f1(st1,st2:ansistring):longint;
var i1,max1:longint;
begin
 max1:=0;
 if (pos(st1,st2)<>0)and(st1<>st2) then exit(0);
 if (pos(st2,st1)<>0)and(st1<>st2) then exit(0);
 for i1:=length(st1) downto 1 do 
  if (pos(copy(st1,length(st1)+1-i1,i1),st2)=1) then max1:=i1;
 f1:=max1;
end;
procedure work(st0:ansistring;x:longint);
var i2:longint;
begin
 i2:=0;
 for i2:=1 to n do begin
  if (b[i2]<2)and(a[x,i2]<>0)then begin
  b[i2]:=b[i2]+1;
  work(st0+copy(st[i2],a[x,i2]+1,length(st[i2])-a[x,i2]),i2);
  b[i2]:=b[i2]-1;
  end;
 end;
 if max<length(st0) then
  begin max:=length(st0);maxst:=st0;end;
end;
begin
 readln(n);
 for i:=1 to n do readln(st[i]);
 readln(ch);
 fillchar(a,sizeof(a),0);
 for i:=1 to n do
  for j:=1 to n do
   a[i,j]:=f1(st[i],st[j]);
 for i:=1 to n do begin
  if st[i][1]=ch then begin
   b[i]:=b[i]+1;work(st[i],i);b[i]:=b[i]-1;
 end;end;
 writeln(max);
end.