#!/usr/bin/python3

n, c = [int(x) for x in input().split()]

# cost[i][j] is the least cost you can guarantee when you've narrowed down the
# true value to interval [i, j].
cost = [[10**9 for _ in range(n+1)] for _ in range(n+1)]

# intervals of length 1
for i in range(n+1):
    cost[i][i] = i

# any longer interval
for l in range(1, n + 1):
    for i in range(n + 1 - l):
        for j in range(i, i + l + 1):
            worst_case = j
            if j > i:
                worst_case = max(worst_case, j + cost[i][j-1])
            if j < i + l:
                worst_case = max(worst_case, c + cost[j+1][i+l])
            cost[i][i + l] = min(cost[i][i+l], worst_case)

print(cost[0][n])