#pragma GCC optimize ( "O3" )
#pragma GCC optimize( "unroll-loops" )
#pragma GCC target ( "sse4.2,fma,avx2,popcnt,lzcnt,bmi2" )
#include <iostream>
#include <string>
#include <stdio.h>
#include <stdint.h>
#include <cassert>
using namespace std;

using ll = long long;

#define TYPE_OF( VAR ) remove_const<remove_reference<decltype( VAR )>::type >::type
#define UNTIE ios_base::sync_with_stdio( false ); cin.tie( nullptr )
#define CEXPR( LL , BOUND , VALUE ) constexpr LL BOUND = VALUE
#define CIN( LL , A ) LL A; cin >> A
#define ASSERT( A , MIN , MAX ) assert( ( MIN ) <= A && A <= ( MAX ) )
#define CIN_ASSERT( A , MIN , MAX ) CIN( TYPE_OF( MAX ) , A ); ASSERT( A , MIN , MAX )
#define GETLINE( A ) string A; getline( cin , A )
#define GETLINE_SEPARATE( A , SEPARATOR ) string A; getline( cin , A , SEPARATOR )
#define FOR( VAR , INITIAL , FINAL_PLUS_ONE ) for( TYPE_OF( FINAL_PLUS_ONE ) VAR = INITIAL ; VAR < FINAL_PLUS_ONE ; VAR ++ )
#define REPEAT( HOW_MANY_TIMES ) FOR( VARIABLE_FOR_REPEAT , 0 , HOW_MANY_TIMES )
#define QUIT return 0
#define COUT( ANSWER ) cout << ( ANSWER ) << "\n";
#define RETURN( ANSWER ) COUT( ANSWER ); QUIT

// 入力フォーマットチェック用
// 余分な改行を許さない
#define CHECK_REDUNDANT_INPUT string VARIABLE_FOR_CHECK_REDUNDANT_INPUT = ""; cin >> VARIABLE_FOR_CHECK_REDUNDANT_INPUT; assert( VARIABLE_FOR_CHECK_REDUNDANT_INPUT == "" ); assert( ! cin );
// #define CHECK_REDUNDANT_INPUT string VARIABLE_FOR_CHECK_REDUNDANT_INPUT = ""; getline( cin , VARIABLE_FOR_CHECK_REDUNDANT_INPUT ); assert( VARIABLE_FOR_CHECK_REDUNDANT_INPUT == "" ); assert( ! cin );
// |N| <= BOUNDを満たすNをSから構築
#define STOI( S , N , BOUND ) TYPE_OF( BOUND ) N = 0; { bool VARIABLE_FOR_POSITIVITY_FOR_STOI = true;  assert( S != "" ); if( S.substr( 0 , 1 ) == "-" ){ VARIABLE_FOR_POSITIVITY_FOR_STOI = false; S = S.substr( 1 ); assert( S != "" ); } assert( S.substr( 0 , 1 ) != " " ); while( S == "" ? false : S.substr( 0 , 1 ) != " " ){ assert( N < BOUND / 10 ? true : N == BOUND / 10 && stoi( S.substr( 0 , 1 ) ) <= BOUND % 10 ); N = N * 10 + stoi( S.substr( 0 , 1 ) ); S = S.substr( 1 ); } if( ! VARIABLE_FOR_POSITIVITY_FOR_STOI ){ N *= -1; } if( S != "" ){ S = S.substr( 1 ); } } 
// 1行で入力される変数の個数が適切か確認（半角空白の個数+1を調べる）
#define COUNT_VARIABLE( S , VARIABLE_NUMBER ) { int size = S.size(); int count = 0; for( int i = 0 ; i < size ; i++ ){ if( S.substr( i , 1 ) == " " ){ count++; } } assert( count + 1 == VARIABLE_NUMBER ); } 

CEXPR( ll , lim_A , 9 );

class Power
{
public:
  ll m_val[lim_A][lim_A];
  inline constexpr Power() : m_val() { FOR( i , 1 , lim_A ){ ll ( &m_val_i )[lim_A] = m_val[i]; ll power = 1; FOR( j , 1 , lim_A ){ m_val_i[j] = power *= i; } } }
};

int main()
{
  UNTIE;
  CEXPR( int , bound_N , 200000 );
  CIN_ASSERT( N , 1 , bound_N );
  CEXPR( ll , bound_A , lim_A - 1 );
  int count[lim_A] = {};
  REPEAT( N ){
    CIN_ASSERT( Ai , 1 , bound_A );
    count[Ai]++;
  }
  CHECK_REDUNDANT_INPUT;
  constexpr Power power{};
  ll answer = 0;
  FOR( i , 0 , lim_A ){
    const ll ( &m_val_i )[lim_A] = power.m_val[i];
    int& count_i = count[i];
    FOR( j , 0 , lim_A ){
      answer += ( m_val_i[j] * count_i ) * count[j];
    }
  }
  RETURN( answer );
}