[BAZIL]

Опишем программно:

const
MaxN = 5000;
var
n : word;
a, b, c : array [0 .. MaxN] of integer;
d : array [0 .. MaxN] of longint;
i : integer;

function min(a,b : longint) : longint;
begin
if a<b then min:=a else min:=b;
end;

begin
assign(input, 'b.in');
reset(input);
assign(output, 'b.out');
rewrite(output);

readln(n);
for i := 1 to n do
read(a[i], b[i], c[i]);

d[0] := 0;
d[1] := a[1];
d[2] := min(a[1]+a[2], b[1]);

for i := 3 to n do
d[i] := min( d[i-1] + a[i], min( d[i-2] + b[i-1], d[i-3] + c[i-2] ) );

writeln(d[n]);
close(input);
close(output);
end.