using System;
public class Program
{
public static void Main()
int n= 123;
int t = 0;
while(n > 0)
int m = n%10;
t = (t * 10) + m;
n = n/10;
}
Console.WriteLine(t);
var i=1;
var temp1=1;
var temp2=0;
var temp3 = 0;
/*for(var j = 1; j<= 20 ;j++)
temp = j;
Console.WriteLine(temp);
j = temp;
}*/
while(temp1<=20)
Console.WriteLine(temp1);
temp2 = temp1; //1, 1, 2
temp1 = temp2 + temp3; //1, 2, 3
temp3 = temp2; //1, 1, 2