#include <bits/stdc++.h>
using namespace std;
#define mp make_pair
#define int long long
#define pb push_back
#define f first
#define s second
#define ld long double
#define sz(x) static_cast<int>((x).size())
#define i5 tuple<int,int,int,int,int>
#define all(x) x.begin(), x.end()
#define iii tuple<int,int,int>
#define eb emplace_back
#define mt make_tuple
#define pll pair<int,int>
#define lol pair<int, vector<int>>
int dp[1000005][3][2];
void chmin(int & x, int v){
x = min(x, v);
}
signed main(){
int n;cin>>n;
vector<int> a(n+1, 0), b(n+1, 0);
for(int i=1;i<=n;i++){
char c;cin>>c;
if(c=='1')a[i]=1;
}
for(int i=1;i<=n;i++){
char c;cin>>c;
if(c=='1')b[i]=1;
}
for(int i=0;i<=n;i++){
for(int j=0;j<3;j++){
for(int k=0;k<2;k++){
dp[i][j][k]=1e15;
}
}
}
dp[0][2][0]=0;
for (int i=1;i<=n;i++){
int add=0;
for(int j1=0;j1<2;j1++){
for(int k=0;k<2;k++){
for(int j2=0;j2<2;j2++){
add=0;
if(!k and j2 == 0 and j1 == 1) add++;
if(k and j2 == 1 and j1 == 0) add++;
if (j2 ^ b[i-1] == 0 and b[i] ^ j1 == 1) add++;
chmin(dp[i][j1][k],dp[i-1][j2][k] + add);
}
if(j1 == k){ // start alternate block, must be equal
add=1; // transition from 2, must +1 immediately
if (b[i-1] ^ b[i-1] == 0 and b[i] ^ j1 == 1) add++;
chmin(dp[i][j1][k], dp[i-1][2][0] + add);
}
}
}
// transition to 2 from 0/1 no normal add, xor add still need
for(int j2=0;j2<2;j2++){
for(int k2=0;k2<2;k2++){
add=0;
if(j2 ^ b[i-1] == 0 and a[i] ^ b[i] == 1) add++;
chmin(dp[i][2][0], dp[i-1][j2][k2]+add);
}
}
// transitionf rom 2 to 2.
add=0;
if(a[i-1] ^ b[i-1] == 0 and a[i] ^ b[i] == 1) add++;
chmin(dp[i][2][0], dp[i-1][2][0] + add);
}
int ans=1e15;
for(int j=0;j<3;j++){
for(int k=0;k<2;k++){
chmin(ans, dp[n][j][k]);
}
}
/*for(int i=0;i<3;i++){
for(int j=0;j<2;j++){
cout<<dp[3][i][j]<<" ";
}
cout<<endl;
}*/
assert(ans < 1e9);
cout<<ans;
}
