#include<bits/stdc++.h> using namespace std; int n; char s[1005]; int cs[27]; char t[1005]; int ct[27]; int main(){ cin >> n; for(int i = 1;i <= n;i++){ cin >> s[i]; cs[int(s[i])-96]++; } for(int i = 1;i <= n;i++){ cin >> t[i]; ct[int(t[i])-96]++; } int cnt(0); for(int i = 1;i <= 26;i++){ if(cs[i]==ct[i] && cs[i]!=0){ cnt++; } } cout << cnt+2; return 0; }