#include <bits/stdc++.h>
#define SKIP 0
#define OFF 1
#define ON 2
#define SKIPXOR 3
#define OFFXOR 4
#define ONXOR 5
#define oper int
using namespace std;
int dist(oper a, oper b){
int ans = 0;
///If the skip/off/on is different, and b is not skip
if(a % 3 != b % 3 && b % 3 != 0) ans++;
///if XOR is taken
if(a <= 2 && b >= 3) ans++;
return ans;
}
int conv(int state, oper o){
switch(o){
case SKIP: return state;
case OFF: return 0;
case ON: return 1;
case SKIPXOR: return state^1;
case OFFXOR: return 1;
case ONXOR: return 0;
default: return -1;
}
}
bitset<1000005> A;
bitset<1000005> B;
int pre[6];
int dp[6];
int main(){
ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
int n; cin >> n;
string SA, SB;
cin >> SA >> SB;
for(int i = 0;i < n;i++){
A[i] = (SA[i] == '1');
B[i] = (SB[i] == '1');
}
fill(dp,dp+6,10234567); dp[0] = 0;
oper operations[6] = {SKIP, OFF, ON, SKIPXOR, OFFXOR, ONXOR};
for(int i = 0;i < n;i++){
swap(dp, pre);
fill(dp,dp+6,10234567);
for(oper curOp : operations){
if(conv(A[i], curOp) != B[i]) continue;
for(oper preOp : operations){
dp[curOp] = min(dp[curOp], pre[preOp] + dist(preOp, curOp));
}
}
}
cout << min({dp[0],dp[1],dp[2],dp[3],dp[4],dp[5]});
}
