#include <bits/stdc++.h>
using namespace std;
#pragma warning(disable : 4996)
#pragma comment(linker, "/STACK:336777216")
inline int nxt() {
  int x;
  scanf("%d", &x);
  return x;
}
inline long long lnxt() {
  long long x;
  scanf("%I64d", &x);
  return x;
}
const int N = (int)1e6 + 100;
const int base = (int)1e9;
const int maxn = (int)1e3 + 100;
const int mod = (int)1e9 + 7;
const int inf = INT_MAX;
const long long ll_inf = LLONG_MAX;
const long double pi = acos((long double)-1.0);
const long double eps = 1e-8;
long long cnt = 0, ans = 0;
void solve() {
  int n;
  cin >> n;
  string s;
  cin >> s;
  for (int i = 1; i < s.size(); ++i) {
    if (s[i] != s[i - 1]) {
      ++i;
      ++cnt;
    }
  }
  cout << n - cnt << endl;
}
int main() {
  int T = 1;
  for (; T; --T) solve();
  return 0;
}
