#include <algorithm> #include <cstdio> #include <cstdlib> #include <cctype> #include <cmath> #include <iostream> #include <queue> #include <list> #include <stack> #include <map> #include <numeric> #include <set> #include <sstream> #include <string> #include <vector> using namespace std; #define REP(i,a,n) for(int i=(a); i<(int)(n); i++) #define rep(i,n) REP(i,0,n) #define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it) #define ALLOF(c) (c).begin(), (c).end() typedef long long ll; int main(){ int N; string S, T; cin >> N; cin >> S; cin >> T; int ret = 0; rep(i,S.length()){ if(S[i] != T[i]) ret++; } cout << ret << endl; return 0; }