#include <iostream>
#include <string>
#include <cstdio>
using namespace std;
double a[3];
int main(){
  for(int i=0;i<3;i++)cin >> a[i];
  double r=(a[1]-a[2])/(a[0]-a[1]);
  double d=a[1]-r*a[0];
  double ans=a[2]*r+d;
  printf("%.0f\n",ans);
  return 0;

}