const   fi='';
        fo='';
        max=30000;
var n,i:longint;
t:array[1..60000] of integer;
f:array[-1..60000] of longint;
r:array[0..59999] of integer;
w:text;
function min(x,y:longint):longint;
begin
    if x>y then min:=y else min:=x;
end;
procedure nhap;
begin
    assign(w,fi);
    reset(w);
    readln(w,n);
    for i:=1 to n do read(w,t[i]);
    for i:=1 to n-1 do read(w,r[i]);
    close(w);
end;
procedure xuly;
begin
        f[0]:=0; f[-1]:=0; r[0]:=max;
        for i:=1 to n do
        f[i]:=min(f[i-1]+t[i],f[i-2]+r[i-1]);
end;
procedure inkq;
begin
        assign(w,fo);
        rewrite(w);
        writeln(w,f[n]);
        close(w);
end;
begin
    nhap;
    xuly;
    inkq;
end.

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