ll@N,@(X,Y)[N];
ll a=X[0]==Y[0]?X[0]:0; ll b=a;
rep(i,1,N) {
    ll na=a,nb=b;
    na=max(na,b+(Y[i]==Y[i-1]?Y[i]:0));
    nb=max(nb,b+(X[i]==Y[i-1]?X[i]:0));
    na=max(na,a+(Y[i]==X[i-1]?Y[i]:0));
    nb=max(nb,a+(X[i]==X[i-1]?X[i]:0));
    ll t=X[i]==Y[i]?X[i]:0;
    a=na+t,b=nb+t;
}
wt(max(a,b));