#include <bits/stdc++.h>
#define REP(i,a,b) for(int i=(a);i<(b);i++)
#define RREP(i,a,b) for(int i=(a);i>=(b);i--)
#define pq priority_queue
#define P pair<int,int>
#define P2 pair<int,P>
#define P3 pair<int,P2>
typedef long long ll; typedef long double ld;
using namespace std;
const int INF=1e9, MOD=1e9+7, around[]={0,1,1,-1,-1,0,-1,1,0,0};
const ll LINF=1e18;
const ld PI=abs(acos(-1));
ll a,b,c;

int main(){
	cin >> a >> b >> c;
	
	cout << a*(c/(a+b-1)+!!(c%(a+b-1)))-(c%(a+b-1)?((a+b-1)*(c/(a+b-1)+!!(c%(a+b-1)))-b>=c?((a+b-1)*(c/(a+b-1)+!!(c%(a+b-1)))-b)-c+1:0):0) << endl;
	return 0;
}