#include <iostream>
#include <string>
using namespace std;
int main() {
int m, tmp1, tmp2, pasos=0;
string a, b;
cin>>m;
cin>>a;
cin>>b;
for(int i=0;i<m;i++){
if(a[i]<=b[i]){
tmp1=b[i]-a[i];
tmp2=(a[i]+10)-b[i];
if(tmp1<=tmp2)
pasos=pasos+tmp1;
else
pasos=pasos+tmp2;
}
else{
tmp1=a[i]-b[i];
tmp2=(b[i]+10)-a[i];
if(tmp1<=tmp2)
pasos=pasos+tmp1;
else
pasos=pasos+tmp2;
}
}
cout<<pasos;
return 0;
}
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