#include<bits/stdc++.h>
using namespace std;
int a[1000005], b[1000005], dp[1000005][6];
int transition(int x, int y)
{
int ans = 0;
if(x%2 == 0 && y%2 == 1) ans++;
if(x/2 != y/2 && y/2 != 2) ans++;
return ans;
}
int result(int num, int x)
{
if(x/2 == 0) return 0;
else if(x/2 == 1) return 1;
else return (num ^ (x%2));
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
int n;
cin>>n;
for(int i = 1; i <= n; i++){
char x; cin>>x;
a[i] = (x == '1');
}
for(int i = 1; i <= n; i++){
char x; cin>>x;
b[i] = (x == '1');
}
for(int i = 0; i <= n; i++) memset(dp[i], 0x3f, sizeof(dp[i]));
dp[0][4] = 0;
for(int i = 0; i < n; i++){
for(int j = 0; j < 6; j++) if(dp[i][j] < 1e9){
for(int k = 0; k < 6; k++){
if(result(a[i+1], k) == b[i+1]){
dp[i+1][k] = min(dp[i+1][k], dp[i][j] + transition(j, k));
}
}
}
}
int ans = 1e9;
for(int i = 0; i < 6; i++) ans = min(ans, dp[n][i]);
cout<<ans;
}
