v 6.5
E
P
=
E
1
−
E
2
+
E
3
−
E
4
+
E
5
−
E
6
.
.
.
±
E
N
E
P
=
E
1
−
E
2
+
E
3
−
E
4
+
E
5
−
E
6
.
.
.
±
E
N
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