HDU_1494_dp

#include<iostream>
#include<cstdio>
#include<cstring>
#define MAX 0X3f3f3f3f
using namespace std;

int l,n,dp[10050][15],a[105],b[105];

int main()
{
    while(~scanf("%d%d",&l,&n))
    {
        for(int i = 0;i < l;i++)   scanf("%d",&a[i]);
        for(int i = 0;i < l;i++)   scanf("%d",&b[i]);
        memset(dp,0x3f,sizeof(dp));
        dp[1][1] = a[0];
        int all = n*l;
        for(int i = 1;i <= all;i++)
        {
            for(int j = 0;j < 15;j++)
            {
                if(dp[i][j] == MAX) continue;
                if(j == 14) dp[i+1][10] = min(dp[i+1][10],dp[i][j]+a[i%l]);
                else    dp[i+1][j+1] = min(dp[i+1][j+1],dp[i][j]+a[i%l]);
                if(j >= 5)  dp[i+1][j-5] = min(dp[i+1][j-5],dp[i][j]+b[i%l]);
            }
        }
        int ans = MAX;
        for(int i = 0;i < 15;i++)   ans = min(ans,dp[all][i]);
        printf("%d\n",ans);
    }
    return 0;
}