#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define srep(i,s,t) for (int i = s; i < t; ++i)
#define drep(i,n) for(int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int,int> P;
#define yn {puts("YES");}else{puts("NO");}
#define MAX_N 200005

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

    ll l = 0, r = 5001001001001001001;
    while(l + 1 < r){
        ll m = (l + r) / 2;
        ll mm = m;
        m--;
        ll tmp = (m-1) / t;
        m -= v*p;
        if(m <= v){
            l = mm;
            continue;
        }
        
        m -= tmp;
        if(m <= v){
            l = mm;
        }else{
            r = mm;
        }
    }
    cout << l << endl;
    return 0;
}