#!/bin/ruby

def countArray(n, x, k)
    array_length = n-2
    if x == 1
        return 0
    else
        not_edges = x*((x-1)**(array_length-1))
        edges = 2*((x-1)**(array_length-1))
        ones_more = (x-1)**(array_length-2)
        return (not_edges-edges+ones_more)% (10**9+7)
    end
end

# def countArray(n, k, x)
#     array_length = n-2
#     if k == array_length
#         answer = (1..k).inject(:*) - 2*(1..k-1).inject(:*) + (1..k-2).inject(:*)
#         return answer % (10**9 + 7)
#     elsif k < array_length
#         return 0
#     elsif k > array_length
#         answer = choose(k, array_length)*(1..array_length).inject(:*) - 2*(1..array_length-1).inject(:*) + (1..array_length-2).inject(:*)
#         return answer % (10**9 + 7)
#     end
# end

def choose(n, k)
    return ((1..n).inject(:*) / ((1..k).inject(:*) * (1..n-k).inject(:*))) % (10**9 + 7)
end

n, k, x = gets.strip.split(' ')
n = n.to_i
k = k.to_i
x = x.to_i
answer = countArray(n, k, x)
puts answer