TakeExam.java

  
public void takeExam(int N) throws Exception {
   
        TestData[] array = new TestData[N];
        for(int i=0;i<N;i++) {
            array[i] = new TestData(input.nextInt(), input.nextInt());            
        }
        Arrays.sort(array, (x,y) -> {
            return (x.actual!=y.actual) ? (x.actual-y.actual) : (x.allowed-y.allowed);
        });
        int best = -1;         
        for(int i=0;i<N;i++) {
            if (best <=array[i].allowed) {
                best = array[i].allowed;
            } else {
                best = array[i].actual;
            }
        }
        System.out.printf("%d\n", best);           
   }

class TestData {
    int actual, allowed;
    public TestData(int actual, int allowed) {
        this.actual = actual;
        this.allowed = allowed;
    }
}