import sys
input = sys.stdin.readline

N,M=map(int,input().split())

def calc(x):
    score=0
    for i in range(1,M+1):
        score+=x%i
    return score

ANS=0

for i in range(N-1000,N+1):
    if i<=0:
        pass
    else:
        ANS=max(ANS,calc(i))

print(ANS)