#include <bits/stdc++.h>
using namespace std;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}
using Int = long long;
const char newl = '\n';

//INSERT ABOVE HERE
signed main(){
  cin.tie(0);
  ios::sync_with_stdio(0);

  Int v,t,p;
  cin>>v>>t>>p;
  auto check=[&](Int x){
    return 1+(x-2)/t+v*(p+1)>=x;
  };

  Int l=0,r=2e18;
  // check(l) = true;
  // check(r) = false;
  while(l+1<r){
    Int m=(l+r)>>1;
    if(check(m)) l=m;
    else r=m;
  }
  cout<<l<<endl;
  return 0;
}