# Enter your code here. Read input from STDIN. Print output to STDOUT

a, b, t = gets.split.map(&:to_i)

avg = (a + b) / 2

def expmod(n, exp, m)
    arr = [n]
    59.times do
        arr << (arr.last * arr.last) % m
    end
    bits = (0..59).select { |b| exp[b] == 1 }
    bits.map { |b| arr[b] }.reduce(:+) % m
end

puts expmod(avg, t, 10 ** 9 + 7)