C++ :

#include <bits/stdc++.h>
using namespace std;

int main()
{
	string a,b,c;
	int vis[100]={0},len,i,j,l,maxx=0,cnt,id;
	cin>>a;
	len=a.length();
	b=a[0];
	cnt=0;
	i=1;
	j=1;
	while(j<len)
	{
		if(a.find(b,i)!=string::npos)
		{
			cnt++;
			if(maxx<cnt)
			{
				id=j;
				maxx=cnt;
				c=b;
			}
			b+=a[i];
			i++;	
		}
		else
		{
			b=a[j++];
			cnt=0;
			i=j;
		}
	}
	cout<<c<<endl;
	cout<<id<<endl;
return 0;
}

Pascal :

var
s:string;
a:array[1..100]of string;
i,j,t,m,h,k:integer;
begin
 readln(s);
 t:=length(s);
 for i:=1 to t-1 do
 begin
  m:=i+1;
  for j:=1 to m do a[j]:=copy(s,j,t-i);
  for h:=1 to m do
  for k:=1 to m do
  if (a[h]=a[k])and(h<>k) then begin writeln(a[k]);writeln(h);exit;end;
 end;
end.