n 走法
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program xtt;
var
  n,i:byte;
  j1,j2,j3:string;
function h(a,b:string):string;
  var i:byte;c:string;
begin
  c:='';
{-5-}  if length(a)<length(b)
         then for i:=1 to length(b)-length(a) do insert('0',a,1)
         else for i:=1 to length(a)-length(b) do insert('0',b,1);{对齐数位}
{-6-}  for i:=length(a) downto 0 do
         if (i=0) then begin if (ord(a[1])+ord(b[1])>=106) then insert('1',c,1) end
         else
           if i=length(a) then
             insert(chr((ord(a[i])+ord(b[i])-96) mod 10+48),c,1)
         else
           insert(chr((ord(a[i])+ord(b[i])-96+
                       ord(ord(a[i+1])+ord(b[i+1])>=106)) mod 10+48),c,1);{加法核心}
  h:=c;
end;
begin
  readln(n);
  j1:='1';j2:='1';j3:='1';
  for i:=2 to n do begin
    j3:=h(j1,j2);
    j2:=j1;j1:=j3;
  end;
  write(j3);readln;
end.

附高精度加法：
{  program xtt;}
     var{申请变量}
{-1-}  a,b,h:string;
{-2-}  i:byte;
     begin{main}
{-3-}  readln(a);{读入}
{-4-}  readln(b);
{-5-}  if length(a)<length(b)
         then for i:=1 to length(b)-length(a) do insert('0',a,1)
         else for i:=1 to length(a)-length(b) do insert('0',b,1);{对齐数位}
{-6-}  for i:=length(a) downto 0 do
         if (i=0) then begin if (ord(a[1])+ord(b[1])>=106) then insert('1',h,1) end
         else
           if i=length(a) then
             insert(chr((ord(a[i])+ord(b[i])-96) mod 10+48),h,1)
         else
           insert(chr((ord(a[i])+ord(b[i])-96+
                       ord(ord(a[i+1])+ord(b[i+1])>=106)) mod 10+48),h,1);{加法核心}
{-7-}writeln(h);{打印}
end.

非高精度解法：
program xtt;
  var
    n,i,j1,j2,j3:word;
begin
  readln(n);
  j1:=1;j2:=1;j3:=1;
  for i:=2 to n do begin
    j3:=j1+j2;
    j2:=j1;j1:=j3;
  end;
  write(j3);readln;
end.

递归解法:
program xtt;
var n:byte;
  function try(n:byte):word;
  begin
    if n<=2 then try:=n else try:=try(n-1)+try(n-2);
  end;
begin
  readln(n);
  write(try(n));
  readln;
end.