#include <bits/stdc++.h> using namespace std; #define int long long #define all(a) (a).begin(),(a).end() #define rep(i, n) for(int i = 0; i < (n); i++) #define pb push_back #define rep1(i, n) for(int i = 1; i <= (n); i++) const int mod = 1e9 + 7; signed main() { int n, m; cin >> n >> m; map<string, int> mp; for (int j = 0; j < m; j++) { string s; cin >> s; mp[s]++; } int ans = 0; for (int i = 1; i < n; i++) { for (int j = 0; j < m; j++) { string s; cin >> s; string s1 = ""; string s2 = ""; for (int i = 0; i < s.size() - 1; i++) { s1 += s[i]; } for (int i = 1; i < s.size(); i++) { s2 += s[i]; } if(mp[s1] > 0){ mp[s] += mp[s1]; } if(mp[s2] > 0){ mp[s] += mp[s2]; } if(i == n - 1){ ans += mp[s]; } } } cout << ans << endl; return 0; }