var reader = require('readline').createInterface({
  input: process.stdin,
  output: process.stdout
});
reader.on('line', (line) => {
  var lines = line.split(" ")
});
reader.on('close', () => {
  var amount = lines[2] - (lines[0] - lines[1]);
  if (amount < 0) {
    amount = 0
  }
  console.log(amount);
});