#include //#include using namespace std; //using namespace atcoder; using ll = long long; using vll = vector; using vvll = vector; using vvvll = vector; using vvvvll = vector; using vb = vector; using vvb = vector; using vvvb = vector; using vvvvb = vector; using vd = vector; using vvd = vector; using vvvd = vector; #define all(A) A.begin(),A.end() #define ALL(A) A.begin(),A.end() #define rep(i, n) for (ll i = 0; i < (ll) (n); i++) using pqr = priority_queue, vector>, greater>>; template bool chmax(T& p, T q, bool C = 1) { if (C == 0 && p == q) { return 1; } if (p < q) { p = q; return 1; } else { return 0; } } template bool chmin(T& p, T q, bool C = 1) { if (C == 0 && p == q) { return 1; } if (p > q) { p = q; return 1; } else { return 0; } } ll gcd(ll(a), ll(b)) { if (b == 0)return a; ll c = a; while (a % b != 0) { c = a % b; a = b; b = c; } return b; } vector>>> G; vll D; vector seen; void dfs(ll n){ seen[n]=1; for(auto v:G[n]){ if(seen[v.first])continue; if(v.second.second==1){ D[v.second.first]=1; } else D[v.second.first]=0; dfs(v.first); } return; } int main() { cin.tie(nullptr); ios::sync_with_stdio(false); ll N; cin>>N; string S; cin>>S; ll an=0; ll b=0; rep(i,N-1){ if(S[i]=='A'&&S[i+1]=='A'){ an++; } else if(S[i]=='A'&&S[i+1]=='B')an++; else if(S[i]=='B'&&S[i+1]=='A'){ if(i!=N-1&&S[i+2]!='B')an++; } else b++; } cout<<(an)+(b>0)<