#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
string x, y;
int dp[1001000][3];
int calc(int n){
int pt[2] = {-2, -2}, pt2=-2;
if (x[0]!=y[0]) dp[0][0]=1, pt2=0;
dp[0][1] = 1;
pt[y[0]-'0']=0;
for (int i=1;i<n;i++){
if (x[i]==y[i]) dp[i][0]=min(dp[i-1][0], dp[i-1][1]);
else{
if (x[i-1]!=y[i-1]) dp[i][0] = min(dp[i-1][0], dp[i-1][1]+1);
else if (pt2==-2) dp[i][0] = min(dp[i-1][0], dp[i-1][1])+1;
else dp[i][0] = min(min(dp[i-1][0], dp[i-1][1]), dp[pt2][0])+1;
pt2=i;
}
if (y[i-1]==y[i]) dp[i][1] = min(dp[i-1][1], dp[i-1][0]+1), pt[y[i]-'0']=i;
else{
if (pt[y[i]-'0']==-2) dp[i][1] = min(dp[i-1][0], dp[i-1][1])+1;
else dp[i][1] = min(min(dp[i-1][0], dp[i-1][1]), dp[pt[y[i]-'0']][1])+1;
pt[y[i]-'0']=i;
}
}
/*for (int i=0;i<n;i++) cout << dp[i][0] << ' ';
cout << '\n';
for (int i=0;i<n;i++) cout << dp[i][1] << ' ';
cout << '\n';*/
return min(dp[n-1][0], dp[n-1][1]);
}
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);
}
for (int j=0;j<2;j++){
for (int i=0;i<n;i++) x[i] = '0'+j;
ans = min(ans, calc(n)+1);
}
cout << ans;
return 0;
}
