#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

#define rep(i, a, b) for (int i = (a); i <= (b); ++i)

map<double, string> f;

int main() {
    cin.tie(0);
    int n; cin >> n;
    string cur = "a";
    rep(i, 1, n) {
        double d; char ch;
        cin >> d >> ch;
        if (f.find(d) == f.end()) {
            f[d] = cur;
            if (cur.back() == 'z') cur += 'a';
            else cur[cur.size() - 1] += 1;
        }
        cout << f[d] << endl;
    }
    return 0;
}