#include <cstdio>
#include <climits>
#include <algorithm>
using namespace std;
int n;
char as[12],bs[12];
int vs[12];

int solve(int pos, int step) {
	if (pos==n) return step;
	int d=vs[pos];
	if (d==0) return solve(pos+1,step);
	int res=INT_MAX;
	for (int tail=pos;tail<n;++tail) {
		vs[tail]=(vs[tail]-d+10)%10;
		res=min(res,solve(pos+1,step+1));
	}
	for (int i=pos;i<n;++i) vs[i]=(vs[i]+d)%10;
	return res;
}

int main() {
	scanf("%d",&n);
	for (int i=0;i<n;++i) scanf(" %c",as+i);
	for (int i=0;i<n;++i) scanf(" %c",bs+i);
	for (int i=0;i<n;++i) vs[i]=(bs[i]-as[i]+10)%10;
	int ans=solve(0,0);
	printf("%d\n",ans);

}