var n,x0,y0,xt,yt,i,dx,dy,ans:longint;
    zb:array[0..1000100,1..2] of longint;
    q:array[0..1000100] of longint;
    h:array[0..10001007] of longint;
    mo:int64;

procedure hash(t:longint);
var k:int64;
    x,y,next:longint;
begin
x:=zb[t,1];y:=zb[t,2];
k:=((x*y mod mo)+mo) mod mo;
next:=h[k];
while next<>0 do
        begin
        if (zb[next,1]=x)and(zb[next,2]=y) then exit;
        next:=q[next];
        end;
inc(ans);
q[t]:=h[k];
h[k]:=t;
end;

begin
assign(input,'loverfinding.in');
assign(output,'loverfinding.out');
reset(input);
rewrite(output);
mo:=10000007;
read(n,x0,y0,xt,yt);
zb[1,1]:=x0;
zb[1,2]:=y0;
hash(1);
for i:=2 to n+1 do
        begin
        if (zb[i-1,1]=xt)and(zb[i-1,2]=yt) then break;
        read(dx,dy);
        zb[i,1]:=zb[i-1,1]+dx;
        zb[i,2]:=zb[i-1,2]+dy;
        hash(i);
        end;
writeln(ans);
close(input);
close(output);
end.