#include<bits/stdc++.h>
using namespace std;

int main(){
    long long v, t, p, ok, ng = 1ll << 60, mid;
    cin >> v >> t >> p;
    while(ok + 1 < ng){
        mid = (ok + ng) >> 1;
        //mid mLの鼻水が出る
        //(mid + t - 1)/ t mLだけすすることができる
        //v * p mL だけ除去できる
        if(v * p + (mid + t - 1) / t + v >= mid)ok = mid;
        else ng = mid;
    }
    cout << ok << endl;
}