#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define ALL(v) v.begin(),v.end()
typedef long long ll;
 
#include<bits/stdc++.h>
using namespace std;

int main(){
  ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  
  int n;
  string s;
  cin>>n>>s;
  
  int cnt=0;
  deque<char> deq;
  rep(i,n) deq.push_back(s[i]);
  while(!deq.empty()){
    cnt++;
    char a=deq.front();
    deq.pop_front();
    while(!deq.empty()){
      if(deq.front()==a) deq.pop_front();
      else break;
    }
    while(!deq.empty()){
      if(deq.back()==a) deq.pop_back();
      else break;
    }
  }
  cout<<cnt<<endl;

  return 0;
}