#include<bits/stdc++.h>
using namespace std;
int n,k,jz=1,ans,sum;
string s;
int main()
{
    cin>>n;
    for(int i=1;i<=n;i++)
    {
        ans=0;
        jz=1;
        cin>>k>>s;
        for(int j=s.size()-1;j>=0;j--)
        {
            if(isdigit(s[j]))
                ans+=(s[j]-48)*jz;
            else 
                ans+=(s[j]-'A'+10)*jz;
            jz*=k;
        }
        sum+=ans;
    }
    cout<<sum;
    return 0;
}