let sum = 0;

const checkBalanced = (num) => {
  const firstDigit = Number(num[0]);
  const secondDigit = Number(num[1]);
  const thirdDigit = Number(num[2]);

  return (firstDigit + thirdDigit) === secondDigit;
};

let currentNum = gets();

while (checkBalanced(currentNum)) {
  sum += Number(currentNum);
  currentNum = gets();
}

print(sum);