#include <bits/stdc++.h> using namespace std; #define ll long long const int N = 2e5 + 5; char a[N]; int n; map<char, int> mp; int ans = 0; string s; void check(int i, int num) { if ((a[i] == a[i + 1]) && (a[i + 1] == a[i + 2]) && i <= n - 2 && !mp[a[i]]) { // s=a[i]+a[i+1]+a[i+2]; mp[a[i]] = 1; ans = max(ans, num + 1); check(i + 3, num + 1); mp[a[i]] = 0; } return; } int main() { ios::sync_with_stdio(0), cin.tie(0), cout.tie(0); cin >> n; for (int i = 1; i <= n; i++) { cin >> a[i]; } for (int i = 1; i <= n - 2; i++) { check(i, 0); } cout << ans << endl; return 0; }