#include#include #include #include using namespace std; typedef long long ll; /* define */ #define sf(a) scanf("%d",&a) #define sfs(a) scanf("%s",a) #define sfI(a) scanf("%I64d",&a) #define pf(a) printf("%d\n",a) #define pfI(a) printf("%I64d\n",a) #define rep(i,a,b) for(int i=(a);i<=(b);i++) #define repd(i,a,b) for(int i=(a);i>=(b);i--) #define rep1(i,a,b) for(int i=(a);i<(b);i++) #define clr0(a) memset(a,0,sizeof(a)) #define clr1(a) memset(a,-1,sizeof(a)) /* define */ const int N = 3100; int a[N],b[N],c[N],dp[N][2]; int n; int dfs(int pos,int fed){ int res=0; if(~dp[pos][fed]) return dp[pos][fed]; if(pos==n && fed) return b[pos]; if(pos==n && !fed) return a[pos]; if(!fed) dp[pos][fed]=max(dfs(pos+1,1)+a[pos],dfs(pos+1,0)+b[pos]); else dp[pos][fed]=max(dfs(pos+1,1)+b[pos],dfs(pos+1,0)+c[pos]); return dp[pos][fed]; } int main(){ sf(n); rep(i,1,n) sf(a[i]); rep(i,1,n) sf(b[i]); rep(i,1,n) sf(c[i]); clr1(dp); int ans; if(n==1){ pf(a[1]); return 0; } ans=max(dfs(2,1)+a[1],dfs(2,0)+b[1]); pf(ans); return 0; }