#include <bits/stdc++.h>
#define int long long
using namespace std;
string s,s1;
int a;
int f[1000001][10];
int next0[1000005];
int next1[1000005];
int dp(int i,int j){
if (i>a){
return 0;
}
if (f[i][j]!=-1){
return f[i][j];
}
f[i][j]=1e7;
int res=1e7;
if (j==1 && s1[i]=='0'){
res= min(res,dp(i+1,1));
}else if (s1[i]=='0'){
res= min(res,1+dp(i+1,1));
}
if (s[i]==s1[i]){
res= min(res,dp(i+1,0));
}
if (j==2 && s1[i]=='1'){
res= min(res,dp(i+1,2));
}else if (s1[i]=='1'){
res= min(res,1+dp(i+1,2));
}
if (j==3 && s1[i]!=s[i]){
res= min(res,dp(i+1,3));
}else if (s1[i]!=s[i]){
res= min(res,1+dp(i+1,3));
}
if (j==5 && s1[i]=='0'){
res= min(res,dp(i+1,5));
}else if (j==5 && s1[i]!='0'){
res= min(res,(s1[i-1]=='0')+dp(i+1,5));
}else{
res= min(res,1+(s1[i]=='1')+dp(i+1,5));
}
if (j==6 && s1[i]=='1'){
res= min(res,dp(i+1,6));
}else if (j==6 && s1[i]!='1'){
res= min(res,(s1[i-1]=='1')+dp(i+1,6));
}else{
res= min(res,1+(s1[i]=='0')+dp(i+1,6));
}
if (j==7 && s1[i]!=s[i]){
res= min(res,dp(i+1,7));
}else if (j==7 && s1[i]==s1[i]){
res= min(res,(s1[i-1]!=s1[i])+dp(i+1,7));
}else{
res= min(res,1+(s1[i]==s[i])+dp(i+1,7));
}
return f[i][j]=res;
}
signed main()
{
// freopen("test.txt", "r", stdin);
// freopen("o2.out", "w", stdout);
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> a;
cin >> s >> s1;
s='#'+s;
s1='#'+s1;
for (int i=1;i<=a;i++){
for (int j=0;j<=9;j++){
f[i][j]=-1;
}
}
cout << dp(1,0) << "\n";
// cout << f[2][5] << "\n";
return 0;
}
/*
8
00100010
10000100
*/
/*
freopen("test.txt", "r", stdin);
freopen("o2.out", "w", stdout);
*/
