Equation - MarisaOJ: Marisa Online Judge

Count the number of integer solutions to the following equation:

$x_1 + x_2 + ... + x_k = n$ with

$x_i \ge p$ . ### Input - A single line contains 3 integers

$n, k, p$ . ### Output - Print the number of solutions, modulo

$10^9+7$ . ### Constraints -

$1 \le n, k, p \le 10^6$ . ### Example Input:

$8 3 1$

Output:

$21$

Topic

Math

Combinatorics

Rating

1300

Solution (0)

Solution