#include <bits/stdc++.h>
using namespace std;
const int minn = 1e6 + 100;
struct ans
{
int a, b;
ans (int a = 0, int b = 0) : a(a), b (b) {};
bool operator < (ans other)
{
if (a < other.a)
{
return 1;
}
if (a > other.a)
{
return 0;
}
return b >= other.b;
}
ans inc()
{
ans ret = *this;
ret.a++;
return ret;
}
ans dec()
{
ans ret = *this;
ret.a--;
return ret;
}
};
ans min(ans a, ans b)
{
if (a < b)
{
return a;
}
return b;
}
ans dp[minn], pd[minn], pdd[minn];
bool a[minn], b[minn];
void inp(bool &x)
{
char y;
cin >> y;
x = (y == '1');
return ;
}
int main()
{
ans minf(0, -1);
int n;
cin >> n;
for (int i = 1;i <= n;i++)
{
inp(a[i]);
}
for (int i = 1;i <= n;i++)
{
inp(b[i]);
}
pd[0] = pdd[0] = {1, 0};
for (int i = 1;i <= n;i++)
{
dp[i] = min(dp[i - 1], min(pd[i - 1], pdd[i - 1]));
if ((dp[i].b & 1) ^ (a[i] ^ b[i]))
{
dp[i].b--;
}
if (dp[i].b == -1)
{
dp[i].b = 1;
dp[i].a++;
}
pd[i] = min(pd[i - 1], min(dp[i - 1].inc(), pdd[i - 1].inc()));
if ((pd[i].b & 1) ^ b[i])
{
pd[i].b--;
}
if (pd[i].b == -1)
{
pd[i].b = 1;
pd[i].a++;
}
pdd[i] = min(pdd[i - 1], min(dp[i - 1].inc(), pd[i - 1].inc()));
if ((pdd[i].b & 1) ^ 1 ^ b[i])
{
pdd[i].b--;
}
if (pdd[i].b == -1)
{
pdd[i].b = 1;
pdd[i].a++;
}
}
cout << min(dp[n].a, min(pd[n].a, pdd[n].a));
}
