Algorithm


A. Olesya and Rodion
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

Olesya loves numbers consisting of n digits, and Rodion only likes numbers that are divisible by t. Find some number that satisfies both of them.

Your task is: given the n and t print an integer strictly larger than zero consisting of n digits that is divisible by t. If such number doesn't exist, print  - 1.

Input

The single line contains two numbers, n and t (1 ≤ n ≤ 1002 ≤ t ≤ 10) — the length of the number and the number it should be divisible by.

Output

Print one such positive number without leading zeroes, — the answer to the problem, or  - 1, if such number doesn't exist. If there are multiple possible answers, you are allowed to print any of them.

Examples
input
Copy
3 2
output
Copy
712

 

Code Examples

#1 Code Example with C++ Programming

Code - C++ Programming

#include<bits/stdc++.h>
using namespace std;


#define ll long long
#define endl '\n'
#define debug(n) cout<<(n)<<endl;
const ll INF = 2e18 + 99;

int main(){
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);

  ll n, t;
  cin>>n>>t;
  if(n == 1 && t == 10){
    cout<<-1<<endl;
    return 0;
  }
  else if(n == 1){
    cout<<t<<endl;
    return 0;
  }
  if(t == 10){
    t = 1;
  }
  cout<<t;
  for(int i = 0; i < n-1; i++){
    cout<<0;
  }

}
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Input

x
+
cmd
3 2

Output

x
+
cmd
712
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Demonstration


Codeforcess Solution 584-A A. Olesya and Rodion ,C++, Java, Js and Python ,584-A,Codeforcess Solution

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