n=int(input())
a=list(map(int,input()))
b=list(map(int,input()))
a=a[::-1]
b=b[::-1]
f=[[0]*2 for i in range(n)]
g=[[0]*2 for i in range(n)]
def get(a,b):
if a>b:return 10-a+b,1,a-b,0
else:return b-a,0,a+10-b,-1
for i in range(n):
if i==0:
x1,del1,x2,del2=get(a[i],b[i])
f[i][0]=x1
g[i][0]=del1
f[i][1]=x2
g[i][1]=del2
#print(f[i][0],f[i][1],g[i][0],g[i][1])
continue
now1=a[i]+g[i-1][0]
now2=a[i]+g[i-1][1]
t1,t2=0,0
if now1>=10:
now1-=10
t1+=1
if now2>=10:
now2-=10
t2+=1
x1,del1,x2,del2=get(now1,b[i])
x3,del3,x4,del4=get(now2,b[i])
if x1+f[i-1][0]<x3+f[i-1][1]:
f[i][0]=x1+f[i-1][0]
g[i][0]=t1+del1
else:
f[i][0]=x3+f[i-1][1]
g[i][0]=t2+del3
if x2+f[i-1][0]<x4+f[i-1][1]:
f[i][1]=x2+f[i-1][0]
g[i][1]=t1+del2
else:
f[i][1]=x4+f[i-1][1]
g[i][1]=t2+del4
print(min(f[n-1]))