a_in, b_in, t = map(int,input().split())
cnt = [0] * 2
a = min(a_in, b_in)
b = max(a_in, b_in)
dif = a - b

ans = []

if a >= t:
    ans.append(a)

elif b >= t:
    s_sum = 0
    while s_sum < t:
        s_sum += a
    if b-t <= s_sum-t:
        ans.append(b)
    else:
        ans.append(s_sum)

else:
    s_sum = 0
    while s_sum < t:
        s_sum += b
        cnt[1] += 1

    ans.append(s_sum)

    while cnt[0] >= 0 and cnt[1] >= 0:
        s_sum += dif
        cnt[0] += 1
        cnt[1] -= 1

        if s_sum >= t:
            ans.append(s_sum)
        else:
            s_sum += a
            cnt[1] += 1

ans.sort()

print(ans[0])