#include <bits/stdc++.h>
#define N 100
using namespace std;
using ll = long long;

ll nck[N][N];

int main() {
	ios_base::sync_with_stdio(false); cin.tie(nullptr);

	for (int i=0; i<N; i++) {
		nck[i][0] = 1;
		for (int j=1; j<=i; j++) {
			nck[i][j] = nck[i-1][j-1] + nck[i-1][j];
		}
	}

	ll a, b, k; cin>>a>>b>>k; --k;
	string s;

	while (a && b) {
		ll x = nck[a+b-1][a-1];
		// cout<<x<<' '<<k<<endl;
		if (x <= k) k -= x, s += 'b', --b;
		else s += 'a', --a;
	}

	while (a--) s += 'a';
	while (b--) s += 'b';

	cout<<s<<endl;
}

#include <bits/stdc++.h>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ld long double
#define ll long long
using namespace std;

#define MOD 1000000007

ll gcd(ll a, ll b) {
    if (b == 0) return a;
    if (a == 0) return b;
    return gcd(b, a % b);
}

ll calc(ll n, ll a, ll b) {
    bool doneA[a + 1], doneB[b + 1];
    memset(doneA, false, sizeof(doneA));
    memset(doneB, false, sizeof(doneB));
    
    ll num = 1;
    for (ll i = 1; i <= n; i++) {
        num *= i;
        for (ll j = 1; j <= a; j++) {
            if (!doneA[j] && num % j == 0) {
                num /= j;
                doneA[j] = true;
            }
        }
        for (ll j = 1; j <= b; j++) {
            if (!doneB[j] && num % j == 0) {
                num /= j;
                doneB[j] = true;
            }
        }
    }
    return num;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int a, b;
    ll k;
    cin >> a >> b >> k;
    
    string s;
    for (int i = 0; i < a; i++) s += 'a';
    for (int j = 0; j < b; j++) s += 'b';
    
    int pos = a;
    int n = a + b;
    k--;
    for (int i = 0; i < n; i++) {
        int cntA = 0, cntB = 0;
        for (int j = i + 1; j < n; j++) {
            if (s[j] == 'a') cntA++;
            else cntB++;
        }
        
        ll ans = calc(n - i - 1, cntA, cntB);
        if (k >= ans) {
            swap(s[i], s[pos]);
            k -= ans;
            pos++;
        }
    }
    
    cout << s << "\n";
    
}

/*
 cnt # a and b
 k -=
 perform the swap
 
 
 
 1: aabbb
 2: ababb
 3: abbab
 4: abbba
 5: baabb
 6: babab
 7: babba
 8: bbaab
 9: bbaba
 10: bbbaa

 */
