// Starcraft 2 enjoyer //
#include <bits/stdc++.h>
// #pragma GCC target("avx2")
// #pragma GCC optimize("O3")
// #pragma GCC optimize("unroll-loops")
using namespace std;
#define LSOne(X) ((X) & -(X))
const int N = 2e5 + 5;
const int M = 2e6 + 5;
const long long K = (1LL << 60) - 1;
const int LG = 20;
const long long INF = 1e18 + 5;
const int C = 26;
const int B = 1000;
const int MOD = 1e9 + 9;
int n, a[N], b[N], ans, l;
bool last = 0;
inline void solve()
{
cin >> n;
for (int x = 1; x <= n; x++)
{
char c;
cin >> c;
a[x] = c - '0';
}
for (int x = 1; x <= n; x++)
{
char c;
cin >> c;
b[x] = c - '0';
}
ans = 0;
l = 1;
while (l <= n)
{
int r = l;
while (r <= n)
{
if (b[r] != b[l])
break;
r++;
}
r--;
int cnt = 0;
for (int x = l; x < r; x++)
{
if (a[x] != a[x + 1])
{
cnt++;
}
}
if (!cnt)
{
if (b[l] == a[l])
{
last = 0;
}
else
{
if (!last)
{
ans++;
last = 1;
}
}
}
else if (cnt == 1)
{
if (a[l] == b[l])
{
ans++;
last = 1;
}
else
{
if (!last)
ans++;
last = 0;
}
}
else
{
ans++;
}
l = r + 1;
// cout << ans << " " << r << "\n";
}
cout << ans << "\n";
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t = 1;
// cin >> t;
for (int x = 1; x <= t; x++)
{
solve();
}
return 0;
}
