#include <iostream>
#include <algorithm>
using namespace std;
const int NMAX = 1e6;
const int inf = 1e9;
int n;
string s;
string t;
int dp[NMAX + 5][3][2];
void trans(int i,int j,int k,int ii,int jj,int kk){
if(i != ii - 1){
return ;
}
if(jj == 0){
if(s[ii] - '0' != ((t[ii] - '0') ^ kk)){
return ;
}
// if(ii == 1 && jj == 0 && kk == 1)printf("1 %d %d %d val %d actual %d\n",i,j,k,dp[i][j][k],dp[i][j][k] + (k == 0 && kk == 1));
dp[ii][jj][kk] = min(dp[ii][jj][kk],dp[i][j][k] + (k == 0 && kk == 1));
return ;
}
if(t[ii] - '0' != ((jj - 1) ^ kk)){
return ;
}
// if(ii == 1 && jj == 0 && kk == 1)printf("2 %d %d %d val %d actual %d\n",i,j,k,dp[i][j][k],dp[i][j][k] + (k == 0 && kk == 1) + (j != jj));
dp[ii][jj][kk] = min(dp[ii][jj][kk],dp[i][j][k] + (k == 0 && kk == 1) + (j != jj));
}
int main(){
cin >> n;
cin >> s;
cin >> t;
s = " " + s;
t = " " + t;
dp[0][0][1] = inf;
dp[0][1][0] = inf;
dp[0][1][1] = inf;
dp[0][2][0] = inf;
dp[0][2][1] = inf;
for(int i = 1;i <= n;i++){
for(int j = 0;j < 3;j++){
for(int k = 0;k < 2;k++){
dp[i][j][k] = inf;
for(int jj = 0;jj < 3;jj++){
for(int kk = 0;kk < 2;kk++){
trans(i - 1,jj,kk,i,j,k);
}
}
}
}
}
int ans = inf;
for(int i = 0;i < 3;i++){
for(int j = 0;j < 2;j++){
ans = min(ans,dp[n][i][j]);
}
}
printf("%d\n",ans);
return 0;
}
