// This program prints 3 and then echoes user input until 
// the user user enters 0.  After the user enters 0, 
// this program outputs 0 twice.

main {
  var nat n;
  var nat m;
  n = 3;
  printNat(n);
  n = printNat( for(77; m=readNat(); 77) {printNat(m);} );
  printNat(n);
}