#include <bits/stdc++.h> //全てのヘッダファイルをインクルード

//ループ
#define rep(i, n) for(int i = 0; i < n; i++) //普通のループ
#define repr(i, n) for(int i = n; i >= 0; i--) //逆ループ

//型名省略
typedef long long ll;
//値
static const ll MX = 100005;
static const ll MX_ll = 1e18;

using namespace std;

//#include "./lib/generic/search.h"

int main(){
    ll v, t, p;
    cin >> v >> t >> p;

    ll hanamizu=0, susuru=t, time=1;
    while(1){
        if(hanamizu+susuru<=v){
            hanamizu+=susuru-1;
            time+=susuru;
            susuru=t;
        }
        else if(hanamizu+susuru>v && p>0){
            time+=v-hanamizu;
            susuru-=v-hanamizu;
            hanamizu=0;
            p--;
        }
        else{
            hanamizu++;
            if(hanamizu>v) break;
            time++;
        }
        //cout << "time:" << time << "hanamizu:"  << hanamizu << "susuru:" << susuru << "kamu:" << p << endl;
    }
    cout << time << endl;
}