Codeforces Round #529 (Div.3) - Bài 1

Polycarp loves ciphers. He has invented his own cipher called repeating.
Repeating cipher is used for strings. To encrypt the string $s=s_1s_2...s_m(1\le m\le 10)$, Polycarp uses the following algorithm:
+ he writes down $s_1$ ones,
+ he writes down $s_2$ twices,
+ he writes down $s_3$ three times,
+...
+ he writes down $s_m$ $m$ times.
For example, if $s="bab"$ the process is: $"b"\to "baa"\to "baabbb"$. So the encrypted $s="bab"$ is $"baabbb"$.
Given string $t$- the result of encryption of some string $s$. Your task is to decrypt it, i.e find the string $s$.
Input
The first line contains integer $n(1\le n\le 55)$- the length of the encrypted string. The second line of the input contains $t$- the result of encryption of some string $s$. It contains only lowercase Latin letters. The length of $t$ is exactly $n$.
It is guarantee that the answer to the test exists.
Output
Print such string $s$ that after encryption it equals $t$.

Examples

input

Copy

6
baabbb

output

Copy

bab

input

Copy

10
ooopppssss

output

Copy

oops

input

Copy

1
z

output

Copy

z

 Solution:

#include<bits/stdc++.h>
using namespace std;
int m;
int main(){
   int n;
   string s;
   cin>>s;
   cin>>s;
   for(int i=0;i<s.size();i+=m){
      cout<<s[i];
      m++;
   }
   return 0;
}