#include <iostream>
#include <iomanip>

using namespace std;

int main() {
    int T, S, D;
    cin >> T >> S >> D;
    
    double time = (double)D / S;
    if(T + time >= 24) {
        cout << fixed << setprecision(10) << 24 - T << endl;
    } else {
        cout << fixed << setprecision(10) << time << endl;
    }
    
    return 0;
}