#include<iostream>
#include<set>
#include<algorithm>
#include<vector>
#include<string>
#include<set>
#include<map>
#include<numeric>
#include<queue>
#include<cmath>
#include<tuple>
using namespace std;
typedef long long ll;
const ll INF=1LL<<60;
typedef pair<int,int> P;
typedef pair<int,P> PP;
const ll MOD=1e9+7;


int main(){
    string S;
    cin>>S;
    int N=S.size();

    vector dp(N+1,vector<vector<ll>>(4,vector<ll>(26,0)));



    /*
    for(int c=0;c<26;c++){
        dp[0][0][c]=1;
    }
    */

    for(int i=0;i<N;i++){
        for(int c=0;c<26;c++){
            //dp[i+1][0][c] +=dp[i][0][c];
            //dp[i+1][1][S[i]-'A']+=dp[i][0][c];
            
            if(S[i]-'A'==c){
                dp[i+1][1][c]+=1;
            }

            dp[i+1][1][c]+=dp[i][1][c];
            if(S[i]-'A'==c){
                dp[i+1][2][c]+=dp[i][1][c];
            }

            dp[i+1][2][c]+=dp[i][2][c];

            if(S[i]-'A'!=c){
                dp[i+1][3][S[i]-'A']+=dp[i][2][c];
            }

            dp[i+1][3][c]+=dp[i][3][c];
        }
    }

    ll ans=0;
    for(int c=0;c<26;c++){
        ans+=dp[N][3][c];
    }

    cout<<ans<<endl;


}