AT_abc329_c [ABC329C] Count xxx

#include <bits/stdc++.h>
using namespace std;
int main() {int n, i = 0, j, len, mx[26] = {0};string s;cin >> n >> s;while (i < n) {j = i;while (j < n && s[j] == s[i]) j++;len = j - i;if (len > mx[s[i] - 'a']) mx[s[i] - 'a'] = len;i = j;}long long ans = 0;for (int k = 0; k < 26; k++) ans += mx[k];cout << ans << endl;return 0;
}