#include <bits/stdc++.h>   using namespace std;   int N;   string A;   string B;   int main() {     ios_base::sync_with_stdio(NULL);     cout.tie(NULL);     cin.tie(NULL);     cin >> N;     cin >> A >> B;     int answer = 0;     for (int i = 0; i < N - 1; ++i) {       if (A[i] == B[i]) continue;       if (A[i + 1] == B[i] && A[i] == B[i + 1])         swap(A[i], A[i + 1]);       else         A[i] = B[i];       ++answer;     }     if (A[N - 1] != B[N - 1]) {       ++answer;       A[N - 1] = B[N - 1];     }     cerr << A << endl;     cout << answer << endl;     return 0;   }   