#include <bits/stdc++.h>

#define int long long
#define double long double

using namespace std;

template <class T>
string tostr(T x) {
	stringstream o;
	o << x;
	return o.str();
}
template <class T>
T sqr(T x) { return x * x; }
template <class T>
T mypow(T x, int n) {
	T r = 1;
	while (n > 0) {
		if (n & 1) r = r * x;
		x = x * x;
		n >>= 1;
	}
	return r;
}

int toint(string s) {
	int v;
	stringstream i(s);
	i >> v;
	return v;
}
bool check(int x, int y, int w, int h) { return x >= 0 && y >= 0 && w > x && h > y; }
int gcd(int a, int b) { return b ? gcd(b, a % b) : a; }
int lcm(int a, int b) { return a / gcd(a, b) * b; }

#define REP(i, a, b) for (int(i) = (a); i < (b); (i)++)
#define rep(i, n) REP(i, 0, n)
#define PER(i, a, b) for (int(i) = (a - 1); i >= (b); (i)--)
#define per(i, n) PER(i, n, 0)
#define each(i, n) for (auto& i : n)
#define clr(a) memset((a), 0, sizeof(a))
#define mclr(a) memset((a), -1, sizeof(a))
#define all(a) (a).begin(), (a).end()
#define dump(val) cerr << #val " = " << val << endl;
#define dum(val) cerr << #val " = " << val;
#define FILL(a, v) fill(a, a + sizeof(a) / sizeof(*a), v)

const int dx[8] = {+1, +0, -1, +0, +1, +1, -1, -1};
const int dy[8] = {+0, -1, +0, +1, -1, +1, -1, +1};
const int mod = 1e9 + 7;
const int INF = 1e9;

const double EPS = 1e-8;
typedef vector<double> vec;
typedef vector<vec> mat;

/*
	1x + 2y = 5
	3x + 4y = 6
	(x = -4, y = 4.5)

	A = {
		{1, 2},
		{3, 4}
	}
	b = {
		5,
		6
	}

	ans = {-4, 4.5}
*/

vec gauss_jordan(const mat& A, const vec& b) {
	int n = A.size();
	mat B(n, vec(n + 1));

	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			B[i][j] = A[i][j];
		}
	}

	for (int i = 0; i < n; i++) B[i][n] = b[i];

	for (int i = 0; i < n; i++) {
		int pivot = i;
		for (int j = i; j < n; j++) {
			if (abs(B[j][i]) > abs(B[pivot][i])) pivot = j;
		}

		swap(B[i], B[pivot]);

		if (abs(B[i][i]) < EPS) return vec();

		for (int j = i + 1; j <= n; j++) B[i][j] /= B[i][i];
		for (int j = 0; j < n; j++) {
			if (i != j) {
				for (int k = i + 1; k <= n; k++) B[j][k] -= B[j][i] * B[i][k];
			}
		}
	}

	vec x(n);

	for (int i = 0; i < n; i++) x[i] = B[i][n];
	return x;
}
#define EQ(n, m) (abs((n) - (m)) < EPS)  // n == m

signed main() {
	double a, b, c;
	cin >> a >> b >> c;

	for (int e = -1e+6; e <= 1e+6; e++) {
		mat A0 = {
		    vec({c, 1}),
		    vec({b, 1}),
		};
		vec B0 = {e, c};

		auto v0 = gauss_jordan(A0, B0);

		mat A1 = {
		    vec({c, 1}),
		    vec({a, 1}),
		};
		vec B1 = {e, b};

		auto v1 = gauss_jordan(A1, B1);

		if (v1.size() && v0.size() && EQ(v0[0], v1[0]) && EQ(v0[1], v1[1])) {
			cout << e << endl;
			return 0;
		}
	}
}