#include<string>
#include<iostream>
#include<algorithm>
using namespace std;
string s1, s2;
int main(){
	int n, i, ans=0;
	cin >> n;
	cin >> s1 >> s2;
	for(i=0;i<n;i++) ans += min(abs(s1[i]-s2[i]),10-abs(s1[i]-s2[i]));
	cout << ans;
}