#define __USE_MINGW_ANSI_STDIO 0
#include <bits/stdc++.h>

using namespace std;
using ll = long long;
#define int ll
using VI = vector<int>;
using VVI = vector<VI>;
using PII = pair<int, int>;

#define FOR(i, a, n) for (ll i = (ll)a; i < (ll)n; ++i)
#define REP(i, n) FOR(i, 0, n)
#define ALL(x) x.begin(), x.end()
#define PB push_back

const ll LLINF = (1LL<<60);
const int INF = (1LL<<30);
const int MOD = 1000000007;

template <typename T> T &chmin(T &a, const T &b) { return a = min(a, b); }
template <typename T> T &chmax(T &a, const T &b) { return a = max(a, b); }
template <typename T> bool IN(T a, T b, T x) { return a<=x&&x<b; }
template<typename T> T ceil(T a, T b) { return a/b + !!(a%b); }
template<class S,class T>
ostream &operator <<(ostream& out,const pair<S,T>& a){
  out<<'('<<a.first<<','<<a.second<<')';
  return out;
}
template<class T>
ostream &operator <<(ostream& out,const vector<T>& a){
  out<<'[';
  REP(i, a.size()) {out<<a[i];if(i!=a.size()-1)out<<',';}
  out<<']';
  return out;
}

int dx[] = {0, 1, 0, -1}, dy[] = {1, 0, -1, 0};

signed main(void)
{
  cin.tie(0);
  ios::sync_with_stdio(false);

  while(true) {
    int n;
    cin >> n;
    if(!n) break;
    vector<string> s(n);
    REP(i, n) cin >> s[i];

    // 座圧しておく
    vector<char> v;
    REP(i, n) REP(j, s[i].size()) v.PB(s[i][j]);
    sort(ALL(v)); v.erase(unique(ALL(v)), v.end());
    REP(i, n) REP(j, s[i].size()) s[i][j] = lower_bound(ALL(v), s[i][j]) - v.begin() + 'A';

    // leading-zero対策
    vector<bool> fro(n, false);
    REP(i, n) if(s[i].size() >= 2) fro[s[i][0]-'A'] = true;

    // 係数を求める
    VI a(15, 0);
    REP(i, n) {
      int tmp = 1;
      for(int j=s[i].size()-1; j>=0; --j) {
        if(i == n-1) a[s[i][j]-'A'] -= tmp;
        else a[s[i][j]-'A'] += tmp;
        tmp *= 10;
      }
    }

    map<PII, int> mp1, mp2;
    int m = v.size(), m2 = m/2;

    function<void(int,int,int)> dfs1 = [&](int x, int sum, int used) {
      if(x == m2) {mp1[{sum, used}]++; return;}
      REP(i, 10) {
        if(fro[x] && i==0) continue;
        if(used&1<<i) continue;
        dfs1(x+1, sum+i*a[x], used | 1<<i);
      }
    };

    function<void(int,int,int)> dfs2 = [&](int x, int sum, int used) {
      if(x == m) {mp2[{sum, used}]++; return;}
      REP(i, 10) {
        if(fro[x] && i==0) continue;
        if(used&1<<i) continue;
        dfs2(x+1, sum+i*a[x], used | 1<<i);
      }
    };

    dfs1(0, 0, 0);
    dfs2(m2, 0, 0);

    vector<pair<PII, int>> vec1(ALL(mp1)), vec2(ALL(mp2));

    for(auto &i: vec2) i.first.first *= -1;
    // cout << vec1 << endl << vec2 << endl;

    int ans = 0;
    int l = 0, r = vec2.size()-1;
    for(;l<vec1.size();) {
      while(r > 0 && vec1[l].first.first > vec2[r].first.first) r--;
      int val1 = vec1[l].first.first, val2 = vec2[r].first.first;
      // cout << l << " " << r << " " << val1 << " " << val2 << endl;
      if(val1 != val2) {
        while(l < vec1.size() && vec1[l].first.first==val1) l++;
        continue;
      }
      for(int i=l; i<vec1.size() && vec1[i].first.first==val1; ++i) {
        for(int j=r; j>=0 && vec2[j].first.first==val2; --j) {
          if((vec1[i].first.second&vec2[j].first.second) == 0) {
            ans += vec1[i].second * vec2[j].second;
          }
        }
      }
      while(l < vec1.size() && vec1[l].first.first==val1) l++;
    }
    cout << ans << endl;
  }

  return 0;
}



Measured memory_bytes: 7816