String2

//zamijeniti string s1 u s2 sa stringom s3
program str2;
var
s1,s2,s3:string;
n,p,k,l,m:integer;

function posk(s1,s2:string;k:integer):integer;
begin
delete (s2,1,k);
if pos(s1,s2)>0 then posk:=pos(s1,s2)+k
            else posk:=0;
end;

begin
writeln('Prvi string je: '); readln(s1);
writeln('Drugi string je: '); readln(s2);
writeln('Treci string je: '); readln(s3);
n:=length(s1); p:=length(s3); k:=0;
while posk(s1,s2,k)>0 do
    begin
    m:=posk(s1,s2,k);
    //writeln (k:5,m:5);
    delete(s2,m,n);
    insert(s3,s2,m);
    k:=m+p-1;
    writeln(s2); readln;
    end;

writeln(s2);
readln;
end.