#include "bits/stdc++.h" #define rep(a,b) for(int a = 0;a < b;a++) #define REP(i, x, n) for(int i = x; i < n; i++) #define P(a) cout << a << endl using namespace std; typedef long long ll; typedef unsigned long long ull; int dx[] = { 1, -1 , 0 , 0 }; int dy[] = { 0, 0, 1, -1 }; unsigned long long str_to_int(std::string str) { unsigned long long ret; std::stringstream ss; ss << str; ss >> ret; return ret; } int main() { int a, b, c; cin >> a >> b >> c; int ans = (c*(a - c) + b*(c - b)) / (a - b); P(ans); }