Cod sursă (job #800226)

#include <bits/stdc++.h>
using namespace std;
//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("popcnt,avx2")
using ll = long long;
//#define int long long
#define forn(i,n) for(int i=0; i<(n); ++i)
#define pb push_back
#define pi pair<int,int>
#define f first
#define s second 
#define vii(a,n) vector<int> a(n); forn(i,n) cin>>a[i];
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
 
const ll inf = 1e18;
const ll mod = 1e9+7;


void solve()
{
	int n; cin>>n;
	vector<int> vi (n);
	forn(i, n)
	  {
	  	string S; cin>>S;
	  	int j = 0;
	  	for(char c : S)
	  	  	j |= (1<<(c-'a'));
	  	vi[i]=j;
	  }
	int k = 0;
	forn(i, n)
	  {
	  	for(int j = i+1; j < n; j++)
	  	  {
	  	  	if(vi[i] && vi[j])
	  	  		k++;
		  }
	  }
	cout<<k<<'\n';
}
 
int32_t main() 
  {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    freopen("cristela.in", "r", stdin);
    freopen("cristela.out", "w", stdout);
    solve();
    return 0;
  }