MODE R = LONG LONG REAL;
R x := -10;
REAL dx = .1;
R s := 0;
WHILE x < 10 DO s +:= long long exp(- (x*x)); x +:= dx OD;
s *:= dx;
R p = long long pi;
print((p, new line, s*s, new line, s*s-p))

#
+3.14159265358979323846264338327950288419716939937510582097494459e  +0
+3.14159265358979323846264338327950288419716938212139827537334506e  +0
-1.72537075456015995340000000000000000000000000000000000000000000e -44
#