Встречено 'until', а ожидалось ';' - PascalABC.NET - Ответ 8725332

Program calculator; //v1.1
var a,b,rez:real;oper,calc:string;flag_start:boolean;
Begin
flag_start:=false;
calc:='N';
rez:=0;
repeat
if(flag_start=false)then
begin
writeln('Are you want to use calculator:Y/N/');
readln(calc);
if(calc<>'Y')then break;
writeln('Please input the first number');
readln(a);
writeln('please choose operator:+,-,*,/,div,mod');
readln(oper);
rez:=a;
writeln('Please input a second number');
readln(a);
case oper of
'+':rez:=rez+a;
'-':rez:=rez-a;
'*':rez:=rez*a;
'/':rez:=rez/a;
'div':rez:=int(round(rez)div round(a));
'mod':rez:=int(round(rez)mod round(a));
else writeln('You chose wrong operator');
end;
end
else
begin
writeln('please choose operator:+,-,*,/,div,mod');
readln(oper);
rez:=a;
writeln('Please input a second number');
readln(a);
case oper of
'+':rez:=rez+a;
'-':rez:=rez-a;
'*':rez:=rez*a;
'/':rez:=rez/a;
'div':rez:=int(round(rez)div round(a));
'mod':rez:=int(round(rez)mod round(a));
else writeln('You chose wrong operator');
end;
writeln('Will you continue to use a calculator?Y/N');
readln(calc);
until(calc='N');
WriteLn('Result is',rez:8:2);
readln;
end.