def naive(n,a,b):
    ans=2**63
    def f(s):
        ans=0
        for i in range(1,n+1):
            ans-=b*s[i]
            if i<n:ans+=a*s[i]*s[i+1]
        return ans
    for bit in range(2**n):
        s=[0]*(n+1)
        for i in range(n):
            if (bit>>i)&1:
                s[i+1]=1
            else:
                s[i+1]=-1
        ans=min(ans,f(s))
    return ans

def sol1(n,a,b):
    dp=[[2**63,2**63] for i in range(n+1)]
    dp[1][1]=-b
    dp[1][0]=b
    for i in range(2,n+1):
        dp[i][1]=min(dp[i-1][1]+a-b,dp[i-1][0]-a-b)
        dp[i][0]=min(dp[i-1][1]-a+b,dp[i-1][0]+a+b)
    return min(dp[n][1],dp[n][0])


def mul(a,b):
    n=len(a)
    res=[[2**63]*n for i in range(n)]
    for i in range(n):
        for j in range(n):
            for k in range(n):
                res[i][j]=min(res[i][j],a[i][k]+b[k][j])
    return res
def mpow(a,k):
    if k==1:return a
    res=mpow(a,k//2)
    res=mul(res,res)
    if k%2==1:
        res=mul(res,a)
    return res
def sol2(n,a,b):
    M=[[a+b,-a+b],[-a-b,a-b]]
    M=mpow(M,n-1)
    dp0=min(M[0][0]+b,M[0][1]-b)
    dp1=min(M[1][0]+b,M[1][1]-b)
    return min(dp0,dp1)


from random import randrange as rd
cnt=0
while 0:
    cnt+=1
    print(cnt)
    n,a,b=rd(2,100),rd(1,100),rd(1,100)
    #ansn=naive(n,a,b)
    ans1=sol1(n,a,b)
    ans2=sol2(n,a,b)
    if ans2!=ans1:
        print(n,a,b)
        break