Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

var scanner = bufio.NewScanner(os.Stdin)

func nextInt() (int, error) {
	s, _ := nextString()
	return strconv.Atoi(s)
}

func nextString() (string, bool) {
	succeeded := scanner.Scan()
	if succeeded {
		return scanner.Text(), succeeded
	}
	return "", succeeded
}

func printArr(arr []string) {
	fmt.Println(strings.TrimRight(fmt.Sprintf("%+v", arr)[1:], "]"))
}

func main() {
	scanner.Split(bufio.ScanWords)

	const maxCapacity = 512 * 1024
	buf := make([]byte, maxCapacity)
	scanner.Buffer(buf, maxCapacity)

	n, _ := nextInt()
	if n == 1 {
		fmt.Println(0)
		return
	}

	s, succeeded := nextString()
	if !succeeded {
		fmt.Errorf("Scan failed")
		return
	}
	nOX := 0
	i := 1
	for {
		if s[i] != s[i-1] {
			nOX++
			i++
		}
		i++
		if i >= n {
			break
		}
	}
	fmt.Println(nOX)
}

C++: #include <algorithm>
#include <cstdint>
#include <functional>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
#include <cstring>

using namespace std;
#define REP(i, n) for (int i = 0; i < n; i++)
#define FOR(i, s, t) for (int i = s; i < t; i++)
#define ALL(obj) obj.begin(), obj.end()

const int iINF = 1e9;
const long long llINF = 1e18;
const int MOD = 1e9 + 7;
template <class T>
inline bool chmax(T& a, T b) {
    if (a < b) {
        a = b;
        return 1;
    }
    return 0;
}
template <class T>
inline bool chmin(T& a, T b) {
    if (a > b) {
        a = b;
        return 1;
    }
    return 0;
}

template <int MOD>
struct ModInt {
    long long val;
    constexpr ModInt(long long v = 0) noexcept : val(v % MOD) {
        if (val < 0) val += MOD;
    }
    constexpr int getmod() { return MOD; }
    constexpr ModInt operator-() const noexcept { return val ? MOD - val : 0; }
    constexpr ModInt operator+(const ModInt& r) const noexcept { return ModInt(*this) += r; }
    constexpr ModInt operator-(const ModInt& r) const noexcept { return ModInt(*this) -= r; }
    constexpr ModInt operator*(const ModInt& r) const noexcept { return ModInt(*this) *= r; }
    constexpr ModInt operator/(const ModInt& r) const noexcept { return ModInt(*this) /= r; }
    constexpr ModInt& operator+=(const ModInt& r) noexcept {
        val += r.val;
        if (val >= MOD) val -= MOD;
        return *this;
    }
    constexpr ModInt& operator-=(const ModInt& r) noexcept {
        val -= r.val;
        if (val < 0) val += MOD;
        return *this;
    }
    constexpr ModInt& operator*=(const ModInt& r) noexcept {
        val = val * r.val % MOD;
        return *this;
    }
    constexpr ModInt& operator/=(const ModInt& r) noexcept {
        long long a = r.val, b = MOD, u = 1, v = 0;
        while (b) {
            long long t = a / b;
            a -= t * b;
            swap(a, b);
            u -= t * v;
            swap(u, v);
        }
        val = val * u % MOD;
        if (val < 0) val += MOD;
        return *this;
    }
    constexpr bool operator==(const ModInt& r) const noexcept { return this->val == r.val; }
    constexpr bool operator!=(const ModInt& r) const noexcept { return this->val != r.val; }
    friend constexpr ostream& operator<<(ostream& os, const ModInt<MOD>& x) noexcept { return os << x.val; }

    friend constexpr istream& operator>>(istream& is, ModInt<MOD>& x) noexcept { return is >> x.val; }
    friend constexpr ModInt<MOD> modpow(const ModInt<MOD>& a, long long n) noexcept {
        if (n == 0) return 1;
        auto t = modpow(a, n / 2);
        t = t * t;
        if (n & 1) t = t * a;
        return t;
    }
};

using mint = ModInt<MOD>;

long long modPow(long long x, long long n, long long mod) {
    long long res = 1;
    while (n > 0) {
        if (n & 1) res = res * x % mod;
        x = x * x % mod;
        n >>= 1;
    }
    return res;
}

long long extGCD(long long a, long long b, long long& x, long long& y) {
    if (b == 0) {
        x = 1;
        y = 0;
        return a;
    }

    long long d = extGCD(b, a % b, y, x);
    y -= a / b * x;
    return d;
}

long long gcd(long long a, long long b) {
    if (b == 0) {
        return a;
    } else {
        return gcd(b, a % b);
    }
}

long long lcm(long long a, long long b) { return a / gcd(a, b) * b; }

template <typename T>
map<T, int> compress(vector<T> x) {
    map<T, int> res;
    sort(x.begin(), x.end());
    x.erase(unique(x.begin(), x.end()), x.end());
    for (int i = 0; i < x.size(); i++) {
        res[x[i]] = i;
    }

    return res;
}

template <typename T>
int former(const vector<T>& v, T x) {
    return upper_bound(v.begin(), v.end(), x) - v.begin() - 1;
}

template <typename T>
int latter(const vector<T>& v, T x) {
    return lower_bound(v.begin(), v.end(), x) - v.begin();
}

template <typename T>
using Vec = vector<T>;
template <typename T>
using VVec = vector<vector<T>>;
using LL = long long;

LL dp[100010];
int main() {
    int N;
    cin >> N;
    string S;
    cin >> S;
    memset(dp, -1, sizeof(dp));
    S.push_back('A');
    dp[0] = 0;
    REP(i, N) {
        if (dp[i] == -1) continue;
        chmax(dp[i + 1], dp[i]);
        if (S[i] == 'O' && S[i + 1] == 'X') chmax(dp[i + 2], dp[i] + 1);
        if (S[i] == 'X' && S[i + 1] == 'O') chmax(dp[i + 2], dp[i] + 1);
    }
    cout << dp[N] << endl;
    return 0;
}

C++: #include <iostream>
#include <string>
#include <algorithm>
#include <functional>
#include <vector>
#include <utility>
#include <cstring>
#include <iomanip>
#include <numeric>
#include <cmath>
using namespace std;
typedef long long ll;
const int INF = 1<<30;
const int MOD = 1e9 + 7;
int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);
    int n; cin >> n;
    string s; cin >> s;
    int ans = 0;
    for(int i = 0; i < n - 1; i++)
    {
        if(s[i] != s[i + 1])
        {
            ans++;
            i++;
        }
    }
    cout << ans << endl;
    return 0;
}

C++: #include <iostream>
#include <string>
using namespace std;

int main()
{
	int n, m = 0;
	string s;

	cin >> n >> s;

	for (int i = 0; i < n - 1; i++) {
		if ((s[i] == 'O' && s[i + 1] == 'X') || (s[i] == 'X' && s[i + 1] == 'O')) {
			m++;
			i++;
		}
	}

	cout << m << endl;
	
	return 0;
}

C++: #include<bits/stdc++.h>
#define rep(i,n,m) for(int i = (n); i <(m); i++)
#define rrep(i,n,m) for(int i = (n) - 1; i >=(m); i--)
using namespace std;
using ll = long long;

int main()
{
    int n;
    cin >> n;
    string s;
    cin >> s;
    vector<int> dp(n+1, 0);
    rep(i, 1, n)
    {
        int ox = 0;
        if (s[i] != s[i-1]) ox = 1;
        dp[i+1] = max(dp[i-1]+ox, dp[i]);
    }
    cout << dp[n] << endl;
    return 0;
}

C++: #include <iostream>
#include <string>
using namespace std;

int main() {
	int N, ans = 0;
	string S;
	cin >> N >> S;
	for (int i = 0; i < N - 1; ++i) {
		if ("OX" == S.substr(i, 2) || "XO" == S.substr(i, 2)) {
			++ans;
			++i;
		}
	}
	cout << ans << endl;
}

C++: #include<iostream>
#include<stdio.h>
#include<string>
#include <algorithm>
#include<cstring>
#include<cmath>
using namespace std;

int main()
{
  int n;
  string s;
  cin>>n;
  cin>>s;
  int ans=0;
  for(int i=0;i<n-1;i++){
    if(s[i]=='O' && s[i+1]=='X'){
      ans++;
      i++;
    }else if(s[i]=='X' && s[i+1]=='O'){
      ans++;
      i++;
    }
  }
  cout<<ans<<endl;
  return 0;
}

C++: #include <bits/stdc++.h>

#define FOR(i, a, b) for (ll (i) = (a); (i) < (b); ++(i))

using namespace std;

using ll = long long;

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << setprecision(20) << fixed;

    ll n;
    string s;
    cin >> n >> s;

    auto pre = s[0];
    auto ans = 0;
    FOR(i, 1, n) {
        if (pre != s[i]) {
            ++ans;
            if (i != n - 1) {
                pre = s[i + 1];
                ++i;
            }
        }
    }
    cout << ans << endl;
    return 0;
}