#include <bits/stdc++.h>
#define fi first
#define se second
#define pb push_back
#define FOR(i, a, b) for (int i = a, _b = b; i <= _b; ++i)
#define FORD(i, a, b) for (int i = a, _b = b; i >= _b; --i)
#define FORLL(i, a, b) for (ll i = a, _b = b; i <= _b; ++i)
#define FORDLL(i, a, b) for (ll i = a, _b = b; i >= _b; --i)
#define all(x) x.begin(), x.end()
#define uni(x) sort(all(x)), x.erase(unique(all(x)), x.end())
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define dbg(...) debug(#__VA_ARGS__, __VA_ARGS__)
template<typename T>
void __print_one(const char *&s, const T &x)
{
while (*s == ' ') ++s;
const char *p = s;
int bal = 0;
while (*s)
{
if (*s == '(') ++bal;
else if (*s == ')') --bal;
else if (*s == ',' && bal == 0) break;
++s;
}
cerr.write(p, s - p) << " = " << x;
if (*s == ',')
{
++s;
cerr << " , ";
}
}
template<typename... Args>
void debug(const char *s, Args... args)
{
cerr << "[ ";
int dummy[] = { 0 , ( __print_one(s, args) , 0 )... };
(void)dummy;
cerr << " ]\n\n";
}
template<class X>
bool maximize(X &a, X b)
{
if (a < b)
{
a = b;
return true;
}
return false;
}
template<class X>
bool minimize(X &a, X b)
{
if (a > b)
{
a = b;
return true;
}
return false;
}
// --------------------------------------------------------------------------------------------
int n, state[1000005], fState[1000005];
ll dp[1000005][3][2];
// --------------------------------------------------------------------------------------------
bool check(int i, int j, int k)
{
int val = (j == 2 ? state[i] : j) ^ k;
return val == fState[i];
}
void solve()
{
cin >> n;
FOR(i, 1, n)
{
char ch; cin >> ch;
state[i] = ch - '0';
}
FOR(i, 1, n)
{
char ch; cin >> ch;
fState[i] = ch - '0';
}
FOR(i, 0, n)
FOR(j, 0, 2)
FOR(k, 0, 1)
dp[i][j][k] = 1e18;
dp[0][2][0] = 0;
FOR(i, 0, n - 1)
{
FOR(j, 0, 2)
FOR(k, 0, 1)
{
if (dp[i][j][k] == ll(1e18)) continue;
FOR(newj, 0, 2)
FOR(newk, 0, 1)
{
if (check(i + 1, newj, newk))
minimize(dp[i + 1][newj][newk], dp[i][j][k] + (newj != 2 && newj != j) + (newk != k && newk == 1));
}
}
}
ll res = 1e18;
FOR(j, 0, 2)
FOR(k, 0, 1)
res = min(res, dp[n][j][k]);
cout << res;
}
signed main()
{
ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define TASK "TEST"
if (fopen(TASK".INP", "r"))
{
freopen(TASK".INP", "r", stdin);
freopen(TASK".OUT", "w", stdout);
}
solve();
return 0;
}
