/*
/+==================================================+\
//+--------------------------------------------------+\\
|.|\\...>>>>>>> Hollwo_Pelw(ass) 's code <<<<<<<...//|.|
\\+--------------------------------------------------+//
\+==================================================+/
*/
#include <bits/stdc++.h>
using namespace std;
// type
typedef long long ll;
typedef long double ld;
// loop
//#define For(i, l, r) for (int i = l; i < r; i++)
//#define ForE(i, l, r) for (int i = l; i <= r; i++)
//#define Ford(i, r, l) for (int i = r; i > l; i--)
//#define FordE(i, r, l) for (int i = r; i >= l; i--)
//#define Fora(i, a) for (auto i : a)
// I/O
#define open(file, in, out) if (fopen(file in, "r")) { \
freopen(file in, "r", stdin); \
freopen(file out, "w", stdout); \
}
#define FAST_IO std::ios::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
#define setpre(n) fixed << setprecision(n)
// pair
#define F first
#define S second
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pdd pair<ld, ld>
// vector & !!?(string)
#define eb emplace_back
#define pb push_back
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define sz(a) a.size()
#define len(a) a.length()
// geometry calculate
#define pi acos(-1.0)
#define g_sin(a) sin(a*pi/180)
#define g_cos(a) cos(a*pi/180)
#define g_tan(a) tan(a*pi/180)
// set val
#define ms0(a) memset(a, 0, sizeof(a));
#define ms1(a) memset(a, 1, sizeof(a));
#define msn1(a) memset(a, -1, sizeof(a));
#define msinf(a) memset(a, 0x3f3f3f, sizeof(a));
// constant
const int mod1 = 998244353, mod = 1e9+7;
const int MAXN = 100005, MAXM = 200010;
// code
#define int long long
int dp[(int) 1e6 + 6][8];
int tr[8][8];
void Solve() {
string a, b; int n;
cin >> n >> a >> b;
for (int i = 0; i < 8; i++){
for (int j = 0; j < 8; j++){
int t = (i | j) ^ i;
while (t){
tr[i][j] += t % 2;
t /= 2;
}
}
}
for (int i = 0; i <= n; i++){
for (int j = 0; j < 8; j++){
dp[i][j] = 1e9;
}
}
dp[0][0] = 0;
for (int i = 1; i <= n; i++){
if (a[i-1] == '1' & b[i-1] == '1'){
for (int j = 0; j < 8; j++){
dp[i][0] = min(dp[i][0], dp[i-1][j] + tr[j][0]);
dp[i][2] = min(dp[i][2], dp[i-1][j] + tr[j][2]);
dp[i][5] = min(dp[i][5], dp[i-1][j] + tr[j][5]);
}
}if (a[i-1] == '1' & b[i-1] == '0'){
for (int j = 0; j < 8; j++){
dp[i][1] = min(dp[i][1], dp[i-1][j] + tr[j][1]);
dp[i][4] = min(dp[i][4], dp[i-1][j] + tr[j][4]);
dp[i][6] = min(dp[i][6], dp[i-1][j] + tr[j][6]);
}
}if (a[i-1] == '0' & b[i-1] == '0'){
for (int j = 0; j < 8; j++){
dp[i][0] = min(dp[i][0], dp[i-1][j] + tr[j][0]);
dp[i][1] = min(dp[i][1], dp[i-1][j] + tr[j][1]);
dp[i][6] = min(dp[i][6], dp[i-1][j] + tr[j][6]);
}
}if (a[i-1] == '0' & b[i-1] == '1'){
for (int j = 0; j < 8; j++){
dp[i][2] = min(dp[i][2], dp[i-1][j] + tr[j][2]);
dp[i][4] = min(dp[i][4], dp[i-1][j] + tr[j][4]);
dp[i][5] = min(dp[i][5], dp[i-1][j] + tr[j][5]);
}
}
}
int ans = 1e9;
for (int i = 0; i < 8; i++){
ans = min(ans, dp[n][i]);
}
// for (int j = 0; j < 8; j ++){
// for (int i = 1; i <= n; i++){
// if (dp[i][j] == 1e9) cout << "X ";
// else cout << dp[i][j] << ' ';
// }
// cout << endl;
// }
cout << ans;
}
signed main(){
open("", ".inp", ".out");
FAST_IO; int TC = 1;
// cin >> TC;
while(TC--) Solve();
return 0;
}
/*
./-=====>>><<<-------- DEBUG -------->>><<<=====-\.
/.................................................\
+====================== INP ======================+
+====================== OUT ======================+
\................................................./
.\-=====>>><<<--------= END =-------->>><<<=====-/.
*/
