var input = require('fs').readFileSync('/dev/stdin', 'utf8');
var arr = input.trim().split("\n");
var n = arr.shift().split(" ")[0] - 0;
var x = [];
for (var i = 1; i <= n; i++) x.push(i);
arr.forEach(function(v) {
   x.splice(x.indexOf(v - 0), 1);
   x.unshift(v - 0);
});
console.log(x.join("\n"));