fun printAS (x) {
  local i, j;
  for i := 0, i<x.length, i:=i+1 do
    for j := 0, j<x[i].length, j:=j+1 do
      write (x[i][j])
    od
  od
}

y := read ();

x := ["abcd", "efgh"];

printAS (x);

for i := 0, i<x.length, i:=i+1 do
  for j := 0, j<x[i].length, j:=j+1 do
    x[i][j] := 'a'
  od
od;

printAS (x)