var s1,s2:string;
si1,si2,dem:longint;
begin
writeln('nhap lan luot 2 chuoi');
readln(s1,s2);si1:=length(s1);si2:=length(s2);
while (s1[si1]=s2[si2])and(si1>1)and(si2>1) do begin
si1:=si1-1;si2:=si2-1;
end;
write('so lan di chuyen la:',si1-1+si2-1);
readln;
end.