#if !defined(__clang__) && defined(__GNUC__)
#include <bits/stdc++.h>
#else
#include <cstdlib>
#include <climits>
#include <iostream>
#include <cstdint>
#include <vector>
#include <string>
#include <complex>
#include <bitset>
#include <queue>
#include <deque>
#include <stack>
#include <utility>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <regex>
#endif //  !defined(__clang__) && defined(__GNUG__)
#if 0
#include <boost/lexical_cast.hpp>
#include <boost/algorithm/string.hpp>
#include <boost/multi_array.hpp>
#include <boost/optional.hpp>
#include <boost/math/common_factor_rt.hpp>
#endif

using namespace std;

int main()
{
    int64_t X, Y, R;
    std::cin >> X >> Y >> R;

    X = std::abs(X);
    Y = std::abs(Y);

    double ans = 0;
    for (int64_t x = X; x <= X + R; ++x) {

        double y;
        double sq = sqrt(R*R - (x - X)*(x - X)) + Y;
        if (std::abs(sq - ceil(sq)) < DBL_EPSILON) {
            y = ceil(sq) + 1;
        }
        else {
            y = ceil(sq);
        }
        ans = std::max(ans, y + x);
    }

    std::cout << (int)ans << std::endl;

    return 0;
}