#include <iostream>
using namespace std;
 
int main() {
    char s[52];
    cin >> s;
 
    int pos[26][2]; 
    int index[26] = {0}; 
 
    // Lưu vị trí xuất hiện của từng ký tự
    for (int i = 0; i < 52; i++) {
        int c = s[i] - 'A'; 
        pos[c][index[c]] = i; 
        index[c]++; 
    }
 
    int dem = 0;
 
    for (int i = 0; i < 26; i++) {
        for (int j = i + 1; j < 26; j++) {
            int A1 = pos[i][0], A2 = pos[i][1];
            int B1 = pos[j][0], B2 = pos[j][1];
 
            if ((A1 < B1 && B1 < A2 && A2 < B2) || (B1 < A1 && A1 < B2 && B2 < A2)) {
               dem++;
            }
        }
    }
 
    cout << dem << endl; 
    return 0;
}

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