function sum (args)

field = subwrd(args,1)

y1 = 1
y2 = 91
x1 = 73
x2 = 217

sum = 0

y = y1
while( y<y2+1 )
x = x1
while( x<x2+1 )
  'set x 'x
  'set y 'y
  'd 'field
sum = sum + subwrd(result,4)
x = x+1
endwhile
y = y+1
endwhile

* Return output
* -------------
say 'The sum = 'sum
return sum
