V, T, P = map(int, input().split())


def is_ok(time):
    if (P+1)*V + (time-1)//T + 1 <= 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 ok


print(meguru(10**50, 0))