#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <string>
#include <sstream>
#include <cmath>
#include <stack>
#include <cctype>
using namespace std;

int main() {

	double b1=0,b2=0,b3=0;

	cin>>b1>>b2>>b3;

/*	int r = (b2-b3)/(b1-b2);
	int d = b2-r*b1;*/

	cout<<(long long)((b2-b3)/(b1-b2)*(b3-b1)+b2)<<endl;
	return 0;
}