#include <bits/stdc++.h>
using namespace std;
#define int long long
#define nl "\n"
#define vi vector<int>
#define ip(x)          \
    for (auto &it : x) \
    cin >> it
#define all(x) x.begin(), x.end()

void solve()
{
    int n, k;
    cin >> n >> k;
    vector<pair<int, char>> a(k);
    for (auto &x : a)
    {
        cin >> x.first >> x.second;
    }
    sort(a.begin(), a.end(), [&](pair<int, char> a, pair<int, char> b)
         { return a.first > b.first; });
    string ans(n, a[0].second);
    for (int i = 1; i < k; i++)
    {
        int x = a[i].first;
        int need = (x + 1) / 2;
        for (int j = 0; j < need; j++)
        {
            ans[x - j] = a[i].second;
        }
    }
    cout << ans << nl;
    // for (auto x : a)
    // {
    //     cout << x.first << " " << x.second << nl;
    // }
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    int t = 1;
    // cin >> t;
    while (t--)
        solve();
}