#include <iostream>

using namespace std;

int solutie(int M, int N, int P) {
    if (N == P) return M;
    int raspuns = M + P;

    if (raspuns > N) raspuns -= N;
    return raspuns;
}

int main () {
    int M, N, P;
    cin >> M >> N >> P;

    cout << solutie(M, N, P) << endl;
    return 0;
}