use std::cmp::*;
use std::io::*;

fn main() {
    let mut s: String = String::new();
    std::io::stdin().read_to_string(&mut s).ok();
    let mut itr = s.trim().split_whitespace();
    let v: usize = itr.next().unwrap().parse().unwrap();
    let t: usize = itr.next().unwrap().parse().unwrap();
    let p: usize = itr.next().unwrap().parse().unwrap();

    // x - x / t - v * p <= v
    let c = |x: usize| x <= v + x / t + v * p;
    let mut ok = 0;
    let mut ng = 1usize << 60;
    while ng - ok > 1 {
        let mid = (ok + ng) >> 1;
        if c(mid) {
            ok = mid;
        } else {
            ng = mid;
        }
    }
    println!("{}", ok + 1);
}