455A - Boredom - CodeForces Solution

n = int(input())
dp = [0]*(10**5+1)
count = [0]*(10**5+1)
inp = list(map(int, input().split()))
if(len(inp) == n):
    for g in inp:
        count[g] += 1
    dp[1] = 1*count[1]
    for i in range(2, 10**5+1):
        dp[i] = max(dp[i-1], dp[i-2]+i*count[i])
    print(max(dp))
else:
    print(0)