#include <bits/stdc++.h>
using namespace std;
const int dy[] = {-1, 0, 1, 0}, dx[] = {0, 1, 0, -1};
const double EPS = 1e-8;
const double PI = acos(-1.0);
int popcount(int n) { return __builtin_popcount(n); }
int popcount(long long n) { return __builtin_popcountll(n); }
template <class T>
int SIZE(T a) {
  return a.size();
}
template <class T>
string IntToString(T num) {
  string res;
  stringstream ss;
  ss << num;
  return ss.str();
}
template <class T>
T StringToInt(string str) {
  T res = 0;
  for (int i = 0; i < SIZE(str); i++) res = (res * 10 + str[i] - '0');
  return res;
}
template <class T>
T gcd(T a, T b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
template <class T>
T lcm(T a, T b) {
  return a / gcd(a, b) * b;
}
template <class T>
void PrintSeq(T &a, int sz) {
  for (int i = 0; i < sz; i++) {
    cout << a[i];
    if (sz == i + 1)
      cout << endl;
    else
      cout << ' ';
  }
}
bool EQ(double a, double b) { return abs(a - b) < EPS; }
void fastStream() {
  cin.tie(0);
  std::ios_base::sync_with_stdio(0);
}
vector<string> split(string str, char del) {
  vector<string> res;
  for (int i = 0, s = 0; i < SIZE(str); i++) {
    if (str[i] == del) {
      if (i - s != 0) res.push_back(str.substr(s, i - s));
      s = i + 1;
    } else if (i == SIZE(str) - 1) {
      res.push_back(str.substr(s));
    }
  }
  return res;
}
const int mod = 1000000007;
vector<vector<long long> > mulm(vector<vector<long long> > &A,
                                vector<vector<long long> > &B) {
  vector<vector<long long> > C(A.size(), vector<long long>(B[0].size()));
  for (int i = 0; i < (int)A.size(); i++) {
    for (int k = 0; k < (int)B.size(); k++) {
      for (int j = 0; j < (int)B[0].size(); j++) {
        C[i][j] = (C[i][j] + A[i][k] * B[k][j]) % mod;
      }
    }
  }
  return C;
}
vector<vector<long long> > pow(vector<vector<long long> > A, long long n) {
  vector<vector<long long> > B(A.size(), vector<long long>(A.size()));
  for (int i = 0; i < (int)A.size(); i++) B[i][i] = 1;
  while (n > 0) {
    if (n & 1) B = mulm(B, A);
    A = mulm(A, A);
    n >>= 1;
  }
  return B;
}
long long N, M, K;
int charToInt(char ch) {
  if (ch >= 'A' && ch <= 'Z') return ch - 'A' + 26;
  return ch - 'a';
}
int main() {
  cin >> N >> M >> K;
  vector<vector<long long> > A(M, vector<long long>(M, 1));
  for (int i = 0; i < K; i++) {
    string s;
    cin >> s;
    A[charToInt(s[1])][charToInt(s[0])] = 0;
  }
  vector<vector<long long> > res = pow(A, N - 1);
  long long ans = 0;
  for (int i = 0; i < M; i++)
    for (int j = 0; j < M; j++) ans = (ans + res[i][j]) % mod;
  cout << ans << endl;
  return 0;
}
