program D;
var
        graf1:array[1..10000,1..10000] of 0..1;
        n,m,i,j,x,y,a:longint;
        f:text;
function tri(ii:longint):boolean;
var
        res:boolean;
begin
        res:=false;
        if (graf1[ii,ii-1]=1)and(graf1[ii-1,ii-2]=1)and(graf1[ii,ii-2]=1)
                then res:=true;
        tri:=res;
end;
{_______________________________}
begin
        assign(f,'penalty.in');
        reset(f);
        readln(f,n,m);
        for i:=1 to n do graf1[i,i]:=0;
        for i:=1 to m do begin
                readln(f,x,y);
                graf1[x,y]:=1;
                graf1[y,x]:=1;
        end;
        read(f,a);
        close(f);
        i:=n;
        x:=0;
        while i>=1 do begin
                if tri(i) then begin
                        if i-1=a then i:=a else i:=i-2;
                end else begin
                        if i<=a then x:=x+1000;
                        i:=i-1;
                end;
        end;
        write(x);
end.