#include <bits/stdc++.h> // clang-format off using namespace std; using ll=long long; using ull=unsigned long long; using pll=pair<ll,ll>; const ll INF=4e18; void print0(){}; template<typename H,typename... T> void print0(H h,T... t){cout<<h;print0(t...);} void print(){print0("\n");}; template<typename H,typename... T>void print(H h,T... t){print0(h);if(sizeof...(T)>0)print0(" ");print(t...);} void perr0(){}; template<typename H,typename... T> void perr0(H h,T... t){cerr<<h;perr0(t...);} void perr(){perr0("\n");}; template<typename H,typename... T>void perr(H h,T... t){perr0(h);if(sizeof...(T)>0)perr0(" ");perr(t...);} void ioinit() { cout<<fixed<<setprecision(15); cerr<<fixed<<setprecision(6); ios_base::sync_with_stdio(0); cin.tie(0); } // clang-format on int main() { ioinit(); ll N; cin >> N; string S; cin >> S; set<pll> changed; bool nochange = false; for (ll i = 0; i < N - 1; i++) { bool cur = (S[i] == 'A'); bool nxt = (S[i + 1] == 'A'); if (cur && nxt) { changed.insert({i, i + 1}); } if (cur && !nxt) { changed.insert({i, i}); } if (!cur && nxt) { changed.insert({i + 1, i + 1}); } if (!cur && !nxt) { nochange = true; } } ll ans = changed.size(); if (nochange) ans++; print(ans); return 0; }