1: 
    2: #include <iostream>
    3:  
    4: using namespace std;
    5: 
    6: int main()
    7: {
    8:     int n;
    9:     int res=0;
   10:     char *s1, *s2;
   11:     
   12:     scanf("%d",&n);
   13:     s1 = new char[n+1];
   14:     s2 = new char[n+1];
   15:     scanf("%s",s1);
   16:     scanf("%s",s2);
   17:     for(int i=0; i<n; i++)
   18:       if(s1[i]!=s2[i]) res++;
   19:     printf("%d",res);
   20:   return 0;
   21: }
   22: