function Main(input) {
  input = input.split(' ')
  var A = parseInt(input[0])
  var B = parseInt(input[1])
  var C = parseInt(input[2])

  if (C > A - B) {
    C -= A - B
    console.log(C)
  } else {
    console.log(0)
  }
}

Main(require('fs').readFileSync('/dev/stdin', 'utf8'))
