/*
in the name of god
*/
//#pragma GCC optimize("Ofast,O3,unroll-loops")
//#pragma GCC target("avx,avx2,fma")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4.1,sse4.2,sse4a,avx,avx2,popcnt,tune=native")
#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> pii;
typedef pair<long long ,long long> pll;
typedef long long ll ;
#define File freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout);
#define all(V) V.begin(),V.end()
#define setprec(x) fixed << setprecision(x)
#define Mp(a,b) make_pair(a,b)
#define len(V) (int)(V.size())
#define sep ' '
#define endl '\n'
#define pb push_back
#define fi first
#define sec second
#define popcount(x) __builtin_popcount(x)
#define lid u<<1
#define rid (lid)|1
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
const ll N = 1e6 + 10,SQ=320,LOG=31;
const ll inf = 1e9 , MD = 1e9 + 7;
inline ll md(ll x){ x %= MD; return (x < 0 ? x + MD : x);}
int n ;
string A,B;
int dp[N][5][2];
vector<vector<int>> V;
int val(int i,int j,int p){
int now = (A[i] == '1');
if(!V[j].empty()) now = V[j].back();
if(p) now ^= 1;
return now;
}
int cost(int i,int j){
if(i == j) return 0;
if(min(len(V[i]),len(V[j])) <= 1){
if(V[i].empty()) return len(V[j]);
if(V[j].empty()) return 0;
if(len(V[i]) == 1){
bool c = 0;
for(auto h : V[j]) c |= (h == V[i][0]);
return len(V[j]) - c;
}
bool c = 0;
for(auto h : V[i]) c |= (h == V[j][0]);
return 1 - c;
}
return 1;
}
int32_t main() {
ios_base::sync_with_stdio(false);cout.tie(0);cin.tie(0);
cin >> n >> A >> B;
A = '#' + A;
B = '#' + B;
V.pb({});
V.pb({1});
V.pb({0});
V.pb({0,1});
V.pb({1,0});
for(int i =0 ;i <= n;i++){
for(int j = 0;j < 5;j++) for(int k = 0;k < 2;k++) dp[i][j][k] = inf;
}
dp[0][0][0] = 0;
for(int i =1 ;i <= n;i++){
for(int j = 0; j < 5;j++){
for(int k = 0 ;k < 2;k++){
for(int p = 0 ;p < 5;p++){
for(int r = 0;r < 2;r++){
if(val(i,p,r) == (B[i] == '1')) dp[i][p][r] = min(dp[i][p][r],dp[i-1][j][k] + cost(j,p) + (r == 1 && k == 0));
}
}
}
}
}
int ans = inf;
for(int j = 0;j < 5;j++){
for(int r = 0;r < 2;r++) ans = min(ans,dp[n][j][r]);
}
cout << ans << endl;
return 0;
}
