#include <iostream>

using namespace std;

string jz = "0123456789aABCDEFGHJKLMNOPQRSTUVWXYZ";
long long suma = 0,sumb = 0;


int main(){
    int n;
    cin >> n;
    string a,b;
    cin >> a >> b;
    
    for(int i = 0;i < a.length();i++){
        for(int j = 0;j < n;i++){
            if(a[i] == jz[j]){
                suma += int(jz[i]);
            }else{
                continue;
            }
        }
    }
    
    for(int i = 0;i < b.length();i++){
        for(int j = 0;j < n;i++){
            if(b[i] == jz[j]){
                sumb += int(jz[i]);
            }else{
                continue;
            }
        }
    }
    
    cout << suma + sumb;
    return 0;
}