function processData(input) {
let string = input.split('\n');
let n = string[0];
let arr = string[1].split(' ').map(Number);
let new_arr = new Set()
let pres ,pass = 0
for(let i=0;i<n;i++){
for(let j = 0;j<n;j++){
if (Math.abs(arr[i] - arr[j]) == 1){
// if (Math.abs(arr[i] - pres) == 1 && Math.abs(arr[i] - pass) == 1 || i==0){
new_arr.add(arr[i])
console.log(arr[i],arr[j])
}
if(true){
new_arr.forEach((a,b) =>{
if(Math.abs(a - new_arr[b]) == 1){
console.log(a)
}
})
}
}
}
}
process.stdin.resume();
process.stdin.setEncoding("ascii");
_input = "";
process.stdin.on("data", function (input) {
_input += input;
});
process.stdin.on("end", function () {
processData(_input);
});
