line = gets.split
n = line[0].to_i
m = line[1].to_i
r = line[2].to_i

if n*m > r
    puts 0
else
    ans = 1
    r -= n*m
    for i in n..n+r-1 do
        ans *= i
    end
    for i in 1..r do
        ans /= i
    end
    puts ans
end