N = int(input())
C,V = map(int,input().split())
# コピーを何回やるか
vmax = 1000
dp = [[0]*vmax for i in range(21)]
dp[0] = [1]*vmax

for i in range(20):
    for j in range(vmax):
        pmoji = dp[i][j]
        if pmoji >= N:
            continue
        for k in range(j,vmax):
            dp[i+1][k] = max(dp[i+1][k],dp[i][j]+(k-j)*pmoji)

cost = float('INF')

for i in range(21):
    for j in range(vmax):
        if dp[i][j] >= N:
            cost = min(cost,i*C+j*V)

print(cost)