var n,i,b,a:longint;
   s:real;
  begin
    readln(n);
    for i:=1 to n do
      begin
        readln(a,b);
        s:=s+a*b;
      end;
    writeln(trunc(s*1.05));
  end.

题解：

var
 s1,s2:string;
 s:real;
 a,b,i,n:longint;
begin
 readln(n);
 for i:=1 to n do
  begin
   readln(a,b);
   s:=s+a*b;
  end;
 s:=s*1.05;
 writeln(trunc(s));
end.

这和题解有什么区别，为什么我的错了