combinationLock540A.py

n=int(input())
a=input()
b=input()
i=0;summ=0
while(i<n):
    aa=int(a[i])
    bb=int(b[i])
    summ+=(min(abs(aa-bb),abs(aa+10-bb),abs(bb-aa+10)))
    i+=1
print(summ)