#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb emplace_back
#define AI(i) begin(i), end(i)
template<class T> bool chmin(T &a, T b) { return b < a && (a = b, true); }
template<class T> bool chmax(T &a, T b) { return a < b && (a = b, true); }
#ifdef KEV
#define DE(args...) kout("[ " + string(#args) + " ] = ", args)
void kout() { cerr << endl; }
template<class T, class ...U> void kout(T a, U ...b) { cerr << a << ' ', kout(b...); }
template<class T> void debug(T l, T r) { while (l != r) cerr << *l << " \n"[next(l) == r], ++l; }
#else
#define DE(...) 0
#define debug(...) 0
#endif
const int MAX_N = 1000010, inf = 1e9;
int n;
char a[MAX_N], b[MAX_N];
int va[MAX_N], vb[MAX_N], pfa[MAX_N], pfb[MAX_N], dp[MAX_N], dif[MAX_N];
int bst[2], good;
int32_t main() {
ios_base::sync_with_stdio(0), cin.tie(0);
cin >> n >> a+1 >> b+1;
for (int i = 1;i <= n;++i) a[i] -= '0', b[i] -= '0';
++n;
for (int i = n;i >= 1;--i) {
va[i] = a[i] ^ a[i-1];
vb[i] = b[i] ^ b[i-1];
}
for (int i = 1;i <= n;++i) {
pfa[i] = pfa[i-1] + va[i];
pfb[i] = pfb[i-1] + vb[i];
dif[i] = dif[i-1] + (va[i] != vb[i]);
}
if (accumulate(va, va+n+1, 0) == 0)
return cout << accumulate(vb, vb + n + 1, 0) / 2 << '\n', 0;
bst[0] = bst[1] = good = inf;
for (int i = 1;i <= n;++i) {
dp[i] = dif[i] + 1;
chmin(dp[i], (va[i]==vb[i]) + pfb[i-1]
+ bst[ a[i-1] ]);
// for (int j = 0;j < i;++j) {
// if ( a[i-1] == a[j+1] ) {
// // dp[j] + 2 + (va[j+1] == vb[j+1]) - pfb[j+1] + (va[i]==vb[i]) + pfb[i-1]
// chmin(dp[i], dp[j] + 2 +
// (va[i]==vb[i]) + (va[j+1]==vb[j+1]) + (pfb[i-1] - pfb[j+1]));
// }
// }
chmin(dp[i], dif[i] + good);
chmin(good, dp[i] - dif[i]);
chmin(bst[ a[i+1] ],
dp[i] + 2 + (va[i+1]==vb[i+1]) - pfb[i+1]);
}
cout << dp[n] / 2 << '\n';
}
