V, T, P = map(int, input().split()) def is_ok(time): if (P+1)*V + (time-1)//T >= time: return True else: return False def meguru(ng, ok): while(abs(ng-ok) > 1): mid = (ng + ok) // 2 if is_ok(mid): ok = mid else: ng = mid return ng print(meguru(10**50, 0))