#include<iostream>#include<cstdio>#include<cstring>#define MAX 0X3f3f3f3fusing 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;}