a, b, c = map(int,input().split())

def is_ok(x):
    p = x//a
    cnt = p*b
    cnt += x-p
    if cnt >= c:
        return True
    return False

def meguru_bisect(ng, ok):
    while (abs(ok - ng) > 1):
        mid = (ok + ng) // 2
        if is_ok(mid):
            ok = mid
        else:
            ng = mid
    return ok
    
print(meguru_bisect(0,10**18+1))