#include <bits/stdc++.h>
using namespace std;
int main() {
    int n; cin >> n;
    n++;
    int out = -1;
    while (n--) {
        string s;
        getline(cin,s);
        vector<int> cnt(26);
        for (char x : s) {
            if (x >= 'A' && x <= 'Z') cnt[x-'A']++;
            if (x >= 'a' && x <= 'z') cnt[x-'a']++;
        }
        bool g = true;
        for (int i = 0; i < 26; i++) {
            if (cnt[i] > 2) g = false;
        }
        out += g;
    }
    cout << out << '\n';
}