text: function solve(input) {
      let elements = new Map();
      let array = input.split(' ').map((el) => el.toLowerCase());
    
      for (let element of array) {
          let counter = 0;
          for (let i = array.length - 1; i >= 0; i--) {
              if (element === array[i]) {
                  counter++;
              }
          }
          elements.set(element, counter);
      }
  
      let kvpArr = Array.from(elements.entries());
      let output = '';
  
      for (let kvp of kvpArr) {
          if (kvp[1] % 2 !== 0) {
              output += kvp[0] + ' ';
          }
      }
      console.log(output);
  }
  
  solve('Java C# Php PHP Java PhP 3 C# 3 1 5 C#');