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

vector<vector<int64_t>> v_comb(100,vector<int64_t>(100));
int64_t comb(int64_t x, int64_t y){
    if(x < 0 || y < 0 || x < y) return 0;
    if(y == 0 || x == y) return 1;
    if(v_comb[x][y] != 0) return v_comb[x][y];
    int64_t rtn = comb(x-1,y-1)+comb(x-1,y);
    v_comb[x][y] = rtn;
    return rtn;
}

int main(){
    int a, b;
    int64_t k;
    cin >> a >> b >> k;
    
    int ai = a;
    int bi = b;
    int64_t mink = 1;
    int64_t maxk = comb(a+b,a)+1;
    string ans;
    for(int i = 0; i < a+b; i++){
        if(k < comb(ai+bi-1,ai-1)+mink){
            ans.push_back('a');
            maxk = comb(ai+bi-1,ai-1)+mink;
            ai--;
        }
        else{
            ans.push_back('b');
            mink = comb(ai+bi-1,ai-1)+mink;
            bi--;
        }
    }

    cout << ans << endl;
}
#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;

constexpr bool typetest = 0;
constexpr int N = 35 + 5;
int a, b;
ll k;

void Read()
{
    cin >> a >> b >> k;
}

ll Pow(ll a, ll b)
{
    ll ans(1);
    for (; b > 0; b >>= 1)
    {
        if ((b & 1))
            ans = ans * a;
        a = a * a;
    }
    return ans;
}

ll Cals(ll x, ll y)
{
    ll ans(0);
    while (y >= x)
        ans += (y /= x);

    return ans;
}

ll Cal(int x, int y)
{
    int n = x + y;
    ll ans(1);
    bitset<N> ck;
    for (int i = 2; i <= n; ++i)
        if (!ck[i])
        {
            ans *= Pow(i, Cals(i, n) - Cals(i, x) - Cals(i, y));
            for (int j = i; j <= n; j += i)
                ck[j] = 1;
        }
    return ans;
}

void Solve()
{
    int n = a + b;
    for (int i = 1; i <= n; ++i)
    {
        //cerr << i << "\n";
        if (a > 0 && Cal(a - 1, b) >= k)
            cout << 'a', --a;
        else
            cout << 'b', k -= Cal(a - 1, b), --b;
    }
}

int32_t main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int t(1);
    if (typetest)
        cin >> t;
    for (int _ = 1; _ <= t; ++_)
    {
        Read();
        Solve();
    }
}