L. Equality
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

Check the correctness of an arithmetic equality that can contain only decimal digits and the signs '+' and '-' (unary and binary). The equality should contain exactly one '='. The equality should not contain other characters including spaces. Leading zeros are allowed. Unary operations can be used multiple times in a row.

Examples of correct, incorrect, and malformed equalities:

  • Correct equalities: '2+2=4', '-5+10+3=2+6', '-+-+-5++10+3=2-+-6', '3=003'.
  • Incorrect but well-formed equalities: '2+2=5', '-+10=10'.
  • Malformed equalities: '2 + 2 = 4', '2*2=4', 'two plus two equals four', '2+2=4+'.
Input

The first line of input contains the equality (up to $$$3 \cdot 10^6$$$ characters, ASCII codes from 32 to 127 inclusive). The line ends with the end of line.

Output

Output 'YES' if the equality is correct, 'NO' if it is incorrect but well-formed, and 'ERROR' if the equality is malformed.

Examples
Input
-5+10+3=2+6
Output
YES
Input
2+2=5
Output
NO
Input
2*2=4
Output
ERROR