#include "bits/stdc++.h"
using namespace std;
#define ll long long
#define forn(i,n) for(int i=0;i<n;i++)
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(),v.rend()
#define pb push_back
#define sz(a) (int)a.size()
const int N = 1e6 + 10, inf = 1e8;
int dp[N][2][2][2][2];
void solve() {
int n; string a, b; cin >> n >> a >> b;
forn(I, N) forn(A, 2) forn(B, 2) forn(C, 2) forn(D, 2) dp[I][A][B][C][D] = inf;
dp[0][0][0][0][0] = 0;
a = "?" + a;
b = "?" + b;
for(int i = 1; i <= n; ++i) {
for(int prev_set_0: {0, 1}) {
for(int prev_set_1: {0, 1}) {
if(prev_set_0 && prev_set_1) continue;
for(int prev_set_xor_before: {0, 1}) {
for(int prev_set_xor_after: {0, 1}) {
if(prev_set_xor_after && prev_set_xor_before) continue;
for(int set_0: {0, 1}) {
for(int set_1: {0, 1}) {
if(set_0 && set_1) continue;
for(int set_xor_before: {0, 1}) {
for(int set_xor_after: {0, 1}) {
if(set_xor_after && prev_set_xor_before) continue;
int newmoves = 0;
if(set_0 && !prev_set_0) ++newmoves;
if(set_1 && !prev_set_1) ++newmoves;
if(set_xor_before && !prev_set_xor_before) ++newmoves;
if(set_xor_after && !prev_set_xor_after) ++newmoves;
int x = (a[i] - '0');
if(set_xor_before) x ^= 1;
if(set_0) x = 0;
if(set_1) x = 1;
if(set_xor_after) x ^= 1;
if(x != b[i] - '0') continue;
dp[i][set_0][set_1][set_xor_before][set_xor_after] =
min(dp[i][set_0][set_1][set_xor_before][set_xor_after],
dp[i - 1][prev_set_0][prev_set_1][prev_set_xor_before][prev_set_xor_after] + newmoves);
}
}
}
}
}
}
}
}
}
int ans = inf;
for(int A: {0, 1}) for(int B: {0, 1}) for(int C: {0, 1}) for(int D: {0, 1}) ans = min(ans, dp[n][A][B][C][D]);
cout << ans << "\n";
}
int32_t main() {
ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
int t = 1;
//cin >> t;
while(t--) {
solve();
}
}
