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

typedef long long ll;
typedef pair<int, int> PII;

const int MAX_N = 3e5+5;

int n;
string s;
map<PII, int> cnt;
int cnt_balance[2 * MAX_N];

bool check(vector<int> vec) {
    sort(vec.begin(), vec.end());
    return vec[0] == vec.back();
}

void brute_force() {
    vector<vector<int>> pref(n + 5, vector<int>(3, 0));
    for (int i = 1; i <= n; i++) {
        pref[i][0] = pref[i-1][0];
        pref[i][1] = pref[i-1][1];
        pref[i][2] = pref[i-1][2];
        pref[i][s[i] - 'a']++;
    }
    int ans = 0;

    for (int l = 1; l <= n; l++) {
        for (int r = l; r <= n; r++) {
            int A = pref[r][0] - pref[l-1][0];
            int B = pref[r][1] - pref[l-1][1];
            int C = pref[r][2] - pref[l-1][2];
            vector<int> vec;
            if (A > 0) vec.push_back(A);
            if (B > 0) vec.push_back(B);
            if (C > 0) vec.push_back(C);
            ans += check(vec);
        }
    }

    cout << ans << '\n';
}

ll get(ll x) {
    return (x * (x + 1)) / 2;
}

ll one_letter() {
    ll res = 0LL;
    int i = 1;
    while (i <= n) {
        int j = i;
        while (j <= n && s[i] == s[j]) j++;
        res += get((ll)(j - i));
        i = j;
    }
    //cout << "One: " << res << '\n';
    return res;
}

ll count_equal(int L, int R, char a, char b) {
    ll res = 0LL;
    int len = R - L;
    
    for (int i = 0; i <= 2*len+3; i++) {
        cnt_balance[i] = 0;
    }

    cnt_balance[len]++;
    int cur = 0;

    for (int i = L; i < R; i++) {
        if (s[i] == a) cur++;
        else cur--;
        res += cnt_balance[cur + len];
        cnt_balance[cur + len]++;
    }

    //cout << "Count equal ";
    //cout << L << ", " << R << ": " << res << '\n'; 

    return res;
}

ll two_letters(char a, char b) {
    int L = 1;
    int R = 1;
    ll res = 0LL;
    for (int i = 1; i <= n; i++) {
        if (s[i] != a && s[i] != b) {
            if (L != R) res += count_equal(L, R, a, b);
            L = R = i + 1;
        } else {
            R++;
        }
    }
    if (L != R) res += count_equal(L, R, a, b);

    //cout << a << ", " << b << ": " << res << '\n';

    return res;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin >> s;
    n = s.size();
    s = '#' + s;

    if (n <= 3005) {
        brute_force();
        return 0;
    }

    ll ans = one_letter();
    ans += two_letters('a', 'b');
    ans += two_letters('b', 'c');
    ans += two_letters('a', 'c');

    int A = 0, B = 0, C = 0;
    cnt[{0, 0}]++;

    for (int i = 1; i <= n; i++) {
        if (s[i] == 'a') A++;
        else if (s[i] == 'b') B++;
        else C++;

        int diff_b = B - A;
        int diff_c = C - A;
        PII tmp = make_pair(diff_b, diff_c);

        //cout << i << ": " << cnt[tmp] << '\n';
        ans += cnt[tmp];
        cnt[tmp]++;
    }

    cout << ans << '\n';

    return 0;
}