C++ :

#include<iostream>
using namespace std;
int main()
{
     int a[12],m=300,sheng=0,z,g=0,c=0,y;
     for(int i=1;i<=12;i++)
     {
     	cin>>a[i];
     	z=sheng+m;//月初总钱 
         
        if((z-a[i])>=0)
		{
         c+=(z-a[i])/100*100;
         sheng=(z-a[i])-(z-a[i])/100*100;
         
        }
        if((z-a[i])<0)
        {
           cout<<-i<<endl;break;
        }
        if(i==12){
        
                  y=c+c/5+sheng;
                   cout<<y;break;
                }
     }
    
     return 0;
	
}

Pascal :

var a:array[1..12]of integer;
    I,total,p:integer;
begin
  {assign(input,'save.in');
  reset(input);
  assign(output, 'save.out');
  rewrite(output);}
  
  total:=0;
  for i:=1 to 12 do
readln(a[i]);
  for i:=1 to 12 do
begin
  total:=total+(300-a[i]);
  if total<0 then
    begin
      write('-',i);
       halt;
    end;
  if total>=100 then
    begin
      p:=p+total div 100;
      total:=total mod 100;
     end;
   end;
writeln(p*120+total);
    {close(input);
    close(output);}
  end.