codeforces 688B Lovely Palindromes

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B. Lovely Palindromes

time limit per test

memory limit per test

input

output

12321, 100001 and 1 are palindrome numbers, while 112 and 1021

2-digit 11 or 6-digit 122221), so maybe she could see something in them.

n from the input and tells what is the n-th even-length positive palindrome number?

Input

n (1 ≤ n ≤ 10100 000).

Output

n-th even-length palindrome number.

Examples

input

1

output

11

input

10

output

1001

Note

10 even-length palindrome numbers are 11, 22, 33, ... , 88, 99 and 1001.

就是回文的定义。

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
char s[1000005];
int main()
{
    scanf("%s",s);
    printf("%s",s);
    int n=strlen(s);
    for(int i=n-1;i>=0;i--)
        printf("%c",s[i]);
    printf("\n");
    return 0;
}