```ts
export function firstUnbalanced(input: string): number {
  const stack: { char: string; index: number }[] = [];
  const closingToOpening: Record<string, string> = {
    ')': '(',
    ']': '[',
    '}': '{'
  };

  for (let i = 0; i < input.length; i++) {
    const char = input[i];

    if (char === '(' || char === '[' || char === '{') {
      stack.push({ char, index: i });
    } else if (char === ')' || char === ']' || char === '}') {
      if (stack.length === 0 || stack[stack.length - 1].char !== closingToOpening[char]) {
        return i;
      }
      stack.pop();
    }
  }

  if (stack.length > 0) {
    return stack[0].index;
  }

  return -1;
}
```