val N:ℕ;
val M:ℕ;

type index = ℤ[-N,N];
type elem  = ℤ[-M,M];
type array = Array[N,elem];

proc maximumValue(a:array): elem
{
  var m:elem; var i:index;
  m ≔ -1; i ≔ 0;
  while i < N do
  {
    if a[i] > m then m ≔ a[i];
    i ≔ i+1;
  }
  return m;
}