#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;


int main(){
    ll A, B, T;
    cin >> A >> B >> T;

    ll ans = LLONG_MAX;
    for(ll y = 0; y < A; ++y){
        ll val = B*y + (T - B*y + A - 1) / A*A;
        smin(ans, val);
        if(B*y >= T)break;
    }
    cout << ans << endl;
}