n = 10
m = n/2
x = 1
y = 2
FUNCTION f k l
IF k >= l
RETURN (-1)^(10-k)
ELSE
RETURN (-1)^k
ENDIF
ENDFUNCTION
i = n
a = 10000
b = 2
WHILE i = i - 1
IF i >= m
x = x + f(i, m) * a/(y = y*(10-i+1))
ELSE
x = x + f(i, m) * (y = y/(i+1))/b
ENDIF
ENDWHILE
x