#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
string x, y;
int dp[1001000][3];
int calc(int n){
for (int i=0;i<n;i++) dp[i][0] = 1e9, dp[i][1] = 1e9, dp[i][2] = 1e9;
dp[0][0] = 1;
if (x[0]!=y[0]) dp[0][1] = 1, dp[0][2] = 1;
else dp[0][2] = 0;
for (int i=1;i<n;i++){
if (x[i]==y[i]){
if (y[i-1]!=y[i]) dp[i][0] = dp[i-1][2]+1;
else dp[i][0] = min(dp[i-1][0], dp[i-1][2]+1);
dp[i][2] = dp[i-1][2];
}
else{
if (y[i-1]!=y[i]) dp[i][0] = dp[i-1][2]+1;
else dp[i][0] = min(dp[i-1][0], dp[i-1][2]+1);
if (x[i-1]==y[i-1]) dp[i][1] = dp[i-1][2]+1;
else dp[i][1] = min(dp[i-1][2]+1, dp[i-1][1]);
dp[i][2] = min(dp[i][0], dp[i][1]);
}
}
//for (int i=0;i<n-1;i++) cout << dp[i][2];
return dp[n-1][2];
}
int main(){
cin.tie(NULL);
ios_base::sync_with_stdio(false);
int n;
cin >> n >> x >> y;
int ans = calc(n);
int pt1=-1, pt2=-1;
for (int i=0;i<n;i++) if(x[i]!=y[i]){
pt1=i; break;
}
for (int i=n-1;i>=0;i--) if(x[i]!=y[i]){
pt2=i; break;
}
if (pt1!=-1){
for (int i=pt1;i<=pt2;i++){
if (x[i]=='0') x[i] = '1';
else x[i] = '0';
}
ans = min(ans, calc(n)+1);
}
cout << ans;
return 0;
}
