WATERJUG_BFS

#include <bits/stdc++.h>
#define MAX 901
using namespace std;

int a, b, c;
int result;
deque<int> qx;      // queue for first jug
deque<int> qy;      // queue for second jug
enum Transition
{
    PourA, PourB, EmptyA, EmptyB, FillA, FillB
};
int visited[MAX][MAX];      // visited[i][j] = 1 -> cell (i, j) visited
int level[MAX][MAX];        // level[i][j] shortest distance from state (0, 0) to (i, j)

void output () {
    cout << result << endl;
}

void dfs () {
    Transition vv;
    level[0][0] = 0;
    int action[10];
    while (!qx.empty()) {
        int x = qx.front();
        qx.pop_front();
        int y = qy.front();
        qy.pop_front();

        for (int i = 0; i < 6; ++i)
            action[i] = 1;
        if (x == 0) {
            action[PourA] = action[EmptyA] = 0;
        }
        if (y == 0) {
            action[PourB] = action[EmptyB] = 0;
        }
        if (x == a) {
            action[FillA] = 0;
        }
        if (y == b) {
            action[FillB] = 0;
        }
        for (int i = 0; i < 6; ++i) {
            if (action[i]) {
                int tmpX;
                int tmpY;
                switch (i) {
                    case PourA:
                        if (y + x > b) {
                            tmpX = x - (b - y);
                            tmpY = b;
                        } else {
                            tmpX = 0;
                            tmpY = y + x;
                        }
                        break;
                    case PourB:
                        if (x + y > a) {
                            tmpX = a;
                            tmpY = y - (a - x);
                        } else {
                            tmpX = x + y;
                            tmpY = 0;
                        }
                        break;
                    case EmptyA:
                        tmpX = 0;
                        tmpY = y;
                        break;
                    case EmptyB:
                        tmpX = x;
                        tmpY = 0;
                        break;
                    case FillA:
                        tmpX = a;
                        tmpY = y;
                        break;
                    case FillB:
                        tmpX = x;
                        tmpY = b;
                        break;
                }
                if (!visited[tmpX][tmpY]) {
                    qx.push_back(tmpX);
                    qy.push_back(tmpY);
                    level[tmpX][tmpY] = level[x][y] + 1;
                    visited[tmpX][tmpY] = 1;
                    // cout << tmpX << tmpY << level[tmpX][tmpY] << i << endl;
                    if (tmpX == c || tmpY == c) {
                        result = level[tmpX][tmpY];
                        return;
                    }
                }
            }
        }
    }

    result = -1;
}

void solve () {
    qx.push_back(0);
    qy.push_back(0);
    visited[0][0] = 1;
    dfs();
}

void input () {
    cin >> a >> b >> c;
}

int main () {
    //freopen("inp", "r", stdin);
    //freopen("out", "w", stdout);
    input();
    solve();
    output();
    return 0;
}