"use strict";
function I(t, i) {
  (this._s = t.split("\n")), (this._c = 0), (this._l = 0), (this._f = i || Number);
}
(I.prototype.a = function(t) {
  var i = this._s[this._l];
  if (i) {
    var s = i.trim().split(" "),
      h = s[this._c];
    return this._c++, s.length === this._c && ((this._c = 0), this._l++), t ? t(h) : this._f(h);
  }
}),
  (I.prototype.l = function(t) {
    var i = this._s[this._l];
    if (i) return (this._c = 0), this._l++, i.split(" ").map(t || this._f);
  }),
  (module.exports = I);

function main(input) {
  var o = new I(input);

  const A = o.a();
  const B = o.a();
  const C = o.a();

  const container1Remaining = A - B;
  const container2Total = C;

  const container2Left = container2Total > container1Remaining ? container2Total - container1Remaining : 0;

  console.log(container2Left);
}

main(require("fs").readFileSync("/dev/stdin", "utf8"));
