#include<iostream>
#include<algorithm>
using namespace std;
 
int main() {
    int n, m, k;
    cin >> n >> m >> k;     // 여자 남자 인턴쉽 수
 
    int tN = n - k;     // 여자가 전부 인턴쉽에 참여할 때
    int tM = m;         // 남자 한 명도 참여하지 않을 때
    int team = 0;
 
    while (tN <= n && tM != 0) {
        if (tN / 2 <= tM) {    
            int tmp = tN / 2;
            team = max(team, tmp); 
        }
        tN++; tM--;  
    }
 
    cout << team << endl;
}

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MTAgMSA1

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