D.cpp

// #pragma GCC optimize("Ofast,unroll-loops")
// #pragma GCC target("avx,avx2,fma")

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

#define ll long long
#define ull unsigned long long
#define dd double
#define ld long double
#define sl(n) scanf("%lld", &n)
#define si(n) scanf("%d", &n)
#define sd(n) scanf("%lf", &n)
#define pll pair <ll, ll>
#define pii pair <int, int>
#define mp make_pair
#define pb push_back
#define all(v) v.begin(), v.end()
#define inf (1LL << 62)
#define loop(i, start, stop, inc) for(ll i = start; i <= stop; i += inc)
#define for1(i, stop) for(ll i = 1; i <= stop; ++i)
#define for0(i, stop) for(ll i = 0; i < stop; ++i)
#define rep1(i, start) for(ll i = start; i >= 1; --i)
#define rep0(i, start) for(ll i = (start-1); i >= 0; --i)
#define ms(n, i) memset(n, i, sizeof(n))
#define casep(n) printf("Case %lld:", ++n)
#define pn printf("\n")
#define pf printf
#define EL '\n'
#define fastio std::ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);

ll n, m, k;

ll solve(ll num)
{
    ll ret = 0;
    for1(i, n) {
        ret += min(m, num / i);
    }
    return ret;
}

int main()
{
    cin >> n >> m >> k;

    ll lo = 1, hi = n*m, ans;
    while(lo <= hi) {
        ll mid = lo+hi >> 1;

        ll got = solve(mid);
        if(got < k) {
            lo = mid + 1;
        }
        else if(got >= k) {
            ans = mid;
            hi = mid - 1;
        }
    }

    cout << ans << EL;

    return 0;
}